smack-a-brother/src/weapon.cpp

#include "weapon.h"
#include "sim.h"
#include <algorithm>
#include <array>
#include <functional>
#include <string_view>

constexpr int ATTACKS_MAX = 255;
constexpr int DAMAGE_STEP = 5;
constexpr int TESLA_LINKS = 5;
constexpr float TESLA_INTERVAL = 0.2f;
constexpr float TESLA_RADIUS = 2;
constexpr float DEGREE = PI / 180;
constexpr float ARROW_LINGER = 2.5f;
constexpr float BOOMERANG_STEP = 2;
constexpr float CASING_BACK = 0.4f;
constexpr float CAPSULE_STEP = 4;
constexpr float CATCH_DISTANCE = 10;
constexpr float DOUBLER_DELAY = 0.15f;
constexpr float FALLOFF_FLOOR = 0.1f;
// How far along a beam its damage bottoms out.
constexpr float BEAM_FADE_REACH = 540;
constexpr float FILL_STRENGTH = 2;
constexpr float TRAJECTORY_REACH = 400;
constexpr float TRAJECTORY_STEP = 4;
constexpr float FIRE_SHAKE = 0.5f;
constexpr float HIT_INTERVAL = 0.25f;
constexpr float HITSTOP_MAX = 3;
constexpr float HITSTOP_PER_DAMAGE = 0.002f;
constexpr float HITSTOP_MIN_DAMAGE = 10;
constexpr float HIT_PARTICLES_PER_DAMAGE = 0.2f;
constexpr float HAMMER_REBOUND = 380;
constexpr float HAMMER_REBOUND_CHARGED = 1.5f;
constexpr float KNOCKBACK_REACH = 1.5f;
constexpr float KNOCKBACK_SPEED = 550;
constexpr float LANCE_LENGTH = 40;
constexpr float MUZZLE_DISTANCE = 18;
constexpr float PROJECTILE_STEP = 8;
constexpr float RAY_STEP = 2;
constexpr float RECOIL_CURVE = 0.75f;
constexpr float ROCKET_TAIL = 7;
constexpr float SLASH_DISTANCE = 12;
constexpr float SLASH_GAP = 14;
constexpr float SHAKE_PER_DAMAGE = 0.003f;
constexpr float SLAM_RATIO = 1.05f;
constexpr float SPEED_DAMAGE = 0.05f;
// A normal attack let go partway through a charge hits harder, up to this much more just short of full.
constexpr float PARTIAL_CHARGE_BONUS = 0.5f;
constexpr float SPEED_UNIT = 100;
constexpr float CONTACT_INTERVAL = 0.4f;
constexpr float WISP_GLIDE = 14;
// How near its fighter's cursor a homing shot stops turning toward it.
constexpr float HOMING_MIN = 10;
constexpr float WISP_LAUNCH_STAGGER = 0.06f;
constexpr float WISP_RELEASE_SPAN = 0.6f;
constexpr float WISP_RING = 18;
constexpr float WISP_RING_GAP = 10;
constexpr float WISP_SPACING = 12;
constexpr float WISP_SPIN = 2.5f;
constexpr float TELEPORT_PROBE = 4;
constexpr float TELEPORT_STEP = 2;
constexpr float CONTACT_KNOCK = 1;
constexpr float SPLASH_EDGE = 0.25f;
constexpr float SPLIT_SCALE = 0.75f;
constexpr float SPLIT_GAP = 0.06f;
constexpr float SPLIT_GAP_MELEE = 0.5f;
constexpr float SPLIT_GAP_THROWN = 0.3f;
constexpr float UPPERCUT_REACH = 16;
constexpr float VOLLEY_GAP = 6;
constexpr float WHIP_CONE = 0.25f;
constexpr float WHIP_HANDLE = 4;
// A plain lash's motion, as shares of its lifetime: the handle draws back until WHIP_WINDUP, drives forward until
// WHIP_THROW and stops, the loop that sends off reaches the tip as it cracks at PATH_OUT, and from WHIP_SETTLE the
// hand draws it back in. Its heading is in radians off the aim, toward the side it rolls over.
constexpr int WHIP_LINKS = 16;
constexpr float WHIP_WINDUP = 0.12f;
constexpr float WHIP_THROW = 0.24f;
constexpr float WHIP_SETTLE = 0.6f;
constexpr float WHIP_RAISED = 1.6f;
constexpr float WHIP_REAR = 2.5f;
constexpr float WHIP_DROOP = -0.9f;
constexpr float WHIP_TAPER = 0.7f;
constexpr float WHIP_KICK = 2.6f;
constexpr float WHIP_WOBBLES = 1;
constexpr float WHIP_DAMPING = 0.02f;
constexpr float WHIP_SAG = 0.6f;
constexpr float WHIP_PULL = 220;
// How far a push tips a dummy: its sideways speed into lean speed for a sudden push (a hit or a blast), and its
// sideways acceleration into lean acceleration for a steady one (a Vacuum's pull).
constexpr float WOBBLE_PER_SPEED = 0.005f;
constexpr float WOBBLE_PER_PULL = 0.05f;
// Vacuum: how fast its pull speeds fighters and shots up toward it, how much of an airblast's knock is left at the edge
// of its reach, and how much of it shoves shots.
constexpr float VACUUM_PULL_RATE = 900;
// How many targets an attack can remember striking (one bit each).
constexpr int STRUCK_MAX = 32;
constexpr float GUST_SHOT_SHARE = 0.16f;
// How much of their spawned life (and range, and falloff) the owner's shots in a Vacuum's cone get back: each time its
// suck nibbles, and all of it from an airblast.
constexpr float VACUUM_RESTORE = 0.1f;
constexpr float GUST_RESTORE = 1;
// How long a Vacuum's suck takes to spin up to its full reach, and to wind back down once let go.
constexpr float VACUUM_SPIN_UP = 0.25f;
constexpr float VACUUM_SPIN_DOWN = 0.2f;
// Grenades: their body's size, how much of a hard knock off a surface they keep, how hard a knock has to be to bounce,
// rolling friction, and the fuse each Ricochet adds.
// How much of a Vacuum's drift a resting mine or a boomerang keeps each tick.
// How slow an arming shot must be going to come to rest.
constexpr float REST_SPEED = 40;
// How fast a shot flies home, against the speed it left at.
constexpr float RETURN_SHARE = 0.5f;
// How hard a bouncing shot must hit a surface to bounce off it.
constexpr float SHOT_BOUNCE_MIN = 60;
// How much of its blast a grenade deals to whoever it clonks on the way.
constexpr float GRENADE_CONTACT_SHARE = 0.2f;
// The double donk: how soon after a marking hit (a grenade's clonk) a blast from the same weapon must land, how much
// harder it hits, and how long its blast lingers, flashing.
constexpr float DONK_WINDOW = 0.25f;
constexpr float DONK_DAMAGE = 3;
constexpr float DONK_FLASH = 0.7f;
// How fast a bouncing shot turns as it rolls.
constexpr float ROLL_SPIN = 3;
// Bolts: their size, gravity (heavier when charged), how far one crawls in a step, how many turns it tries a step
// (from into its surface round to away from it), how far it reaches for a surface on landing, and how long one lasts at
// most.
constexpr float CRAWL_STEP = 2;
constexpr int CRAWL_TURNS = 12;
constexpr float CRAWL_SNAP = 10;
constexpr Burst CASING_BURST = {.gravity = 700, .life = 0.6f, .size = 1, .speed = 110, .spread = 0.35f, .count = 1};
constexpr Burst BLAST_BURST = {.gravity = 200, .life = 0.5f, .size = 4, .speed = 220, .count = 20};
constexpr Burst HIT_BURST = {.gravity = 300, .speed = 180, .spread = PI / 2, .count = 6};
constexpr Burst IMPACT_BURST = {.speed = 80, .count = 5};
constexpr Burst SLAM_BURST = {
    .angle = -PI / 2, .gravity = 600, .life = 0.6f, .size = 4, .speed = 260, .spread = PI / 2.5f, .count = 24};
constexpr Burst SMOKE_BURST = {.life = 0.3f, .size = 2, .speed = 40, .spread = 0.4f, .count = 1};
constexpr Burst SPARK_BURST = {.speed = 200, .spread = PI / 2, .count = 12};
constexpr Burst TRAIL_BURST = {.life = 0.25f, .size = 2, .speed = 120, .spread = 0.2f, .count = 2};
constexpr Burst WARP_BURST = {.gravity = -60, .life = 0.4f, .size = 2, .speed = 50, .spread = PI, .count = 1};
constexpr Burst PORTAL_BURST = {.life = 0.4f, .size = 3, .speed = 140, .spread = PI, .count = 14};

// Flies a thrown weapon back toward the hand, reporting whether it got there.
static bool is_caught(Fighter& fighter, Attack& attack)
{
    Vec2 toHand = fighter.hand_get() - attack.position;
    float distance = vec2_length(toHand);
    attack.position = attack.position + vec2_normalize(toHand) * std::min(distance, attack.stats.speed * TICK);
    return distance < CATCH_DISTANCE;
}

// Moves a returning shot one tick toward its fighter's hand at half the speed it left at, sliding along any surface in
// the way (trying each axis alone when the straight step is blocked). Reports whether it's done: caught, or wedged with
// nowhere to go, which breaks it off with a burst.
static bool shot_return(Sim& sim, Fighter& fighter, Attack& attack)
{
    Vec2 toHand = fighter.hand_get(attack.hand) - attack.position;
    float distance = vec2_length(toHand);
    if (distance < CATCH_DISTANCE)
        return true;
    // Small steps, so it can't skip through a thin platform either.
    float travel = std::min(distance, attack.stats.speed * RETURN_SHARE * TICK);
    int steps = travel / BOOMERANG_STEP + 1;
    Vec2 step = vec2_normalize(toHand) * (travel / steps);
    for (int i = 0; i < steps; i++)
    {
        bool isMoved = false;
        for (Vec2 tried : {step, Vec2{step.x, 0}, Vec2{0, step.y}})
        {
            Vec2 next = attack.position + tried;
            if ((tried.x == 0 && tried.y == 0) || sim.world.is_blocking_at(next))
                continue;
            attack.position = next;
            isMoved = true;
            break;
        }
        if (isMoved)
            continue;
        sim.cues->burst_spawn(IMPACT_BURST, attack.position, 0, attack.owner);
        return true;
    }
    return false;
}

// Bounces a direction off the wall between from (open) and to (solid), flipping whichever axis crossed into it, or
// mirroring it off a ramp's surface.
static Vec2 reflect_get(Sim& sim, Vec2 from, Vec2 to, Vec2 direction)
{
    Vec2 normal = sim.world.normal_get(to);
    if (normal.x != 0 || normal.y != 0)
        return direction - normal * (2 * vec2_dot(direction, normal));
    bool isWallX = sim.world.is_blocking_at({to.x, from.y});
    bool isWallY = sim.world.is_blocking_at({from.x, to.y});
    if (!isWallX && !isWallY)
    {
        isWallX = true;
        isWallY = true;
    }
    return {isWallX ? -direction.x : direction.x, isWallY ? -direction.y : direction.y};
}

// Plays the sound of a projectile striking a wall or a target. Hooks latch and rockets and fireballs explode
// with their own sounds.
static void impact_play(Sim& sim, AttackKind kind)
{
    switch (kind)
    {
        case ATTACK_ARROW:
            sim.cues->sound_play(SOUND_IMPACT_ARROW);
            break;
        case ATTACK_BOOMERANG:
            sim.cues->sound_play(SOUND_IMPACT_BOOMERANG);
            break;
        case ATTACK_BULLET:
            sim.cues->sound_play(SOUND_IMPACT_BULLET);
            break;
        case ATTACK_FLAIL:
            sim.cues->sound_play(SOUND_FLAIL_LAND);
            break;
        case ATTACK_GRENADE:
            sim.cues->sound_play(SOUND_GRENADE_BOUNCE);
            break;
        case ATTACK_MINE:
            sim.cues->sound_play(SOUND_IMPACT_MINE);
            break;
        case ATTACK_PROJECTILE:
        case ATTACK_WISP:
            sim.cues->sound_play(SOUND_IMPACT_BLASTER);
            break;
        default:
            break;
    }
}

// Spends one of an attack's ricochets on a bounce, adding to its later damage. Flames go quietly, as there are so
// many.
static void ricochet_count(Sim& sim, Attack& attack)
{
    attack.bounces--;
    attack.ricochets++;
    if (attack.def()->kind == ATTACK_FLAME)
        return;
    sim.cues->sound_play(SOUND_RICOCHET);
    sim.cues->burst_spawn(IMPACT_BURST, attack.position, 0, attack.owner);
}

// Turns a projectile off the wall it's about to enter, starting its range, lifetime and damage falloff afresh from
// there.
static void ricochet(Sim& sim, Attack& attack, Vec2 next)
{
    attack.velocity = reflect_get(sim, attack.position, next, attack.velocity);
    attack.angle = vec2_angle(attack.velocity);
    attack.origin = attack.position;
    attack.lifeStart = attack.time;
    ricochet_count(sim, attack);
}

// What stops an attack moving through the world: walls and platform tops for most, walls alone for wisps.
using WallCheck = bool (World::*)(Vec2);

// Moves an attack toward a point in small steps, so a fast one can't skip through a thin wall. It stops on the last
// clear step, writing the first blocked one, and returns whether it reached a wall.
static bool is_wall_reached(Sim& sim, Attack& attack, Vec2 to, Vec2& wall, WallCheck isWall = &World::is_blocking_at)
{
    Vec2 from = attack.position;
    int steps = vec2_length(to - from) / PROJECTILE_STEP + 1;
    for (int step = 1; step <= steps; step++)
    {
        Vec2 point = vec2_lerp(from, to, (float)step / steps);
        if ((sim.world.*isWall)(point))
        {
            wall = point;
            return true;
        }
        attack.position = point;
    }
    return false;
}

// Walks the capsule in small steps, writing the first point that touches the rect.
static bool is_capsule_in_rect(Capsule capsule, Rect rect, Vec2& point)
{
    Vec2 delta = capsule.to - capsule.from;
    int steps = vec2_length(delta) / CAPSULE_STEP + 1;

    for (int i = 0; i <= steps; i++)
    {
        Vec2 sample = capsule.from + delta * ((float)i / steps);
        Vec2 closest = {std::clamp(sample.x, rect.x, rect.x + rect.w), std::clamp(sample.y, rect.y, rect.y + rect.h)};
        if (vec2_length(sample - closest) > capsule.radius)
            continue;
        point = closest;
        return true;
    }
    return false;
}

// Whether an attack's reach and end go by how long it has been out (see lifetime_get), which the Hourglass stretches:
// one timed by a lifetime, a shot with falloff that flies (not an instant, which reaches its range at once), or one on
// a rope or chain (whose length grows with its flight, see Weapons::is_spawned).
static bool is_aging(const AttackDef& def, const AttackStats& stats)
{
    return stats.lifetime > 0 || (def.isFalloff && !def.isInstant) || def.isTethered;
}

// How far an attack reaches as fired, its speed and lifetime grown by its fighter's trinkets (see reach_get).
static float reach_at_get(Attack& attack)
{
    const AttackDef& def = *attack.def();
    if (attack.stats.range > 0 || def.path == PATH_ARC)
        return attack.stats.range;
    return attack.stats.speed * attack.lifetime * (def.path == PATH_RETURN ? PATH_OUT : 1);
}

// Ranged shots lose damage linearly over their fade: full at the muzzle, down to a floor at its end (a fraction of 1)
// and past it.
float falloff_at(float fraction)
{
    return 1 - std::min(1.0f, fraction) * (1 - FALLOFF_FLOOR);
}

// How far along a beam or a hook's rope its damage bottoms out, or never along anything else.
float falloff_reach_get(Attack& attack)
{
    AttackKind kind = attack.def()->kind;
    if (kind == ATTACK_BEAM)
        return BEAM_FADE_REACH;
    return kind == ATTACK_HOOK ? attack.stats.range : RANGE_INFINITE;
}

// A shot's falloff goes by how long it has flown. A beam's goes by distance along it to the point, and a hook's by how
// far it reached from where it was thrown.
static float falloff_get(Attack& attack, Vec2 point)
{
    AttackKind kind = attack.def()->kind;
    if (!attack.def()->isFalloff)
        return 1;
    if (kind == ATTACK_BEAM)
        return falloff_at(vec2_length(point - attack.position) / falloff_reach_get(attack));
    if (kind == ATTACK_HOOK)
        return falloff_at(vec2_length(attack.position - attack.origin) / falloff_reach_get(attack));
    return falloff_at(attack.life_get() / attack.fade);
}

// How long a shot flies before it ends: as long as its base speed takes to cover its range (so a faster one goes
// further, and one that accelerates speeding up as it goes), unless its data gives one (a punch, a flame's linger, a
// grenade's fuse, a mine's wait).
static float lifetime_get(const AttackDef& def, AttackStats& stats)
{
    AttackKind kind = def.kind;
    if (stats.lifetime > 0)
        return stats.lifetime;
    return stats.speed > 0 ? flight_time_get(def, stats.speed, stats.range) : 0;
}

float flight_time_get(const AttackDef& def, float speed, float distance)
{
    if (def.accelerate <= 0)
        return distance / speed;
    float top = speed * def.speedup;
    float rise = (top - speed) / def.accelerate;
    float risen = (speed + top) / 2 * rise;
    if (distance > risen)
        return rise + (distance - risen) / top;
    return (std::sqrt(speed * speed + 2 * def.accelerate * distance) - speed) / def.accelerate;
}

// How far a rocket, mine or fireball's explosion reaches. It grows with trinkets but not with the attack's own size, so
// a big fireball keeps its listed area.
float blast_area_get(Attack& attack)
{
    return attack.stats.area * attack.scale / attack.stats.scale;
}

// What ricochets and falloff do to an attack's damage at a point.
static float multiplier_get(Attack& attack, Vec2 point)
{
    return (1 + attack.ricochets * RICOCHET_BONUS) * falloff_get(attack, point);
}

// How hard an attack hits right now against its plain damage, with its speed bonus, ricochets and falloff.
float strength_get(Attack& attack, Vec2 point)
{
    return attack.bonus * multiplier_get(attack, point);
}

// A weapon's muzzle as weapons.anm2 places it: from the hand along the aim (x) and to its side (y, flipped facing
// left).
struct Muzzle
{
    const char* weapon;
    float x;
    float y;
};

// Each weapon's muzzle by its place in WEAPON_DEFS, from the Muzzle nulls in weapons.anm2 (read in at build time, see
// sim.cmake), or MUZZLE_DISTANCE straight ahead for a weapon without one.
static constexpr std::array<Vec2, WEAPON_COUNT> MUZZLES = [] {
    constexpr Muzzle NULLS[] = {WEAPON_MUZZLES{nullptr, 0, 0}};
    std::array<Vec2, WEAPON_COUNT> muzzles;
    for (int weapon = 0; weapon < WEAPON_COUNT; weapon++)
    {
        muzzles[weapon] = {MUZZLE_DISTANCE, 0};
        for (const Muzzle& null : NULLS)
            if (null.weapon && std::string_view(null.weapon) == WEAPON_DEFS[weapon].name)
                muzzles[weapon] = {null.x, null.y};
    }
    return muzzles;
}();

// Where an attack's shots leave its weapon, held at its origin and pointing along its angle: the weapon's muzzle (see
// MUZZLES), turned to the angle and mirrored facing left.
Vec2 muzzle_get(Attack& attack)
{
    Vec2 muzzle = MUZZLES[attack.weapon];
    float side = attack.isLeft ? -1 : 1;
    return attack.origin + vec2_polar(attack.angle, muzzle.x) + vec2_polar(attack.angle + PI / 2, muzzle.y * side);
}

// How much of an attack's black fill its color takes over, from none at plain damage to all at FILL_STRENGTH.
float fill_get(float strength)
{
    return std::clamp((strength - 1) / (FILL_STRENGTH - 1), 0.0f, 1.0f);
}

// Where a plain lash's handle points at a share of its lifetime, off the aim (see WHIP_WINDUP): eased back slowly,
// driven forward sharply over the top, held along the aim through the crack, then drooping.
static float lash_heading_get(float time)
{
    time = std::max(0.0f, time);
    if (time < WHIP_WINDUP)
    {
        float ease = 1 - time / WHIP_WINDUP;
        return math_lerp(WHIP_RAISED, WHIP_REAR, 1 - ease * ease);
    }
    if (time < WHIP_THROW)
    {
        float drive = (time - WHIP_WINDUP) / (WHIP_THROW - WHIP_WINDUP);
        return math_lerp(WHIP_REAR, 0, drive * drive * (3 - 2 * drive));
    }
    if (time < PATH_OUT)
        return 0;
    return WHIP_DROOP * std::min(1.0f, (time - PATH_OUT) / (WHIP_SETTLE - PATH_OUT));
}

// The way a heading off a plain lash's aim points, turning toward the side it rolls over.
static Vec2 lash_direction_get(Attack& attack, float heading)
{
    Vec2 forward = vec2_polar(attack.aimAngle, 1);
    Vec2 up = attack.isLeft ? Vec2{-forward.y, forward.x} : Vec2{forward.y, -forward.x};
    return forward * math_cos(heading) + up * math_sin(heading);
}

// A plain lash as a chain of links from the end of its handle. Each link points where the handle pointed a moment
// before, longer toward the tip but less so for the lighter links, so the handle's stop rolls a loop down it that
// straightens the tip as it cracks. After, the tip snaps back over and wobbles out ever slower while the slack whip
// sags, and the hand draws it in.
std::vector<Vec2> lash_get(Attack& attack)
{
    float time = attack.progress_get();
    float recoil = std::max(0.0f, (time - PATH_OUT) / (1 - PATH_OUT));
    float slack = time < PATH_OUT ? std::max(0.0f, 1 - time / WHIP_THROW) : std::min(1.0f, 2 * recoil);
    float kick = time < PATH_OUT
                     ? 0
                     : WHIP_KICK * math_sin(2 * PI * WHIP_WOBBLES * std::sqrt(recoil)) * math_pow(WHIP_DAMPING, recoil);
    float drawn = time < WHIP_SETTLE ? 1 : 1 - (time - WHIP_SETTLE) / (1 - WHIP_SETTLE);
    float step = attack.length * drawn / WHIP_LINKS;
    Vec2 forward = vec2_polar(attack.aimAngle, 1);
    Vec2 up = lash_direction_get(attack, PI / 2);
    // Slack, it sags toward straight down: behind the hand while drawn back, ahead of it after the crack.
    float rest = time < PATH_OUT ? WHIP_REAR : 0;
    float down = rest + std::remainder(math_atan2(up.y, forward.y) - rest, 2 * PI);

    std::vector<Vec2> points = {attack.position};
    for (int i = 0; i < WHIP_LINKS; i++)
    {
        float along = (i + 0.5f) / WHIP_LINKS;
        float heading = lash_heading_get(time - (PATH_OUT - WHIP_THROW) * math_pow(along, WHIP_TAPER));
        heading += kick * along * along;
        heading += (down - heading) * WHIP_SAG * slack * along;
        points.push_back(points.back() + lash_direction_get(attack, heading) * step);
    }
    return points;
}

// A fighter other than the attacker that's still alive, any dummy, or a block that isn't broken.
// Whether one fighter's attacks can touch another: always in a match, but in the sandbox only between two fighters that
// both have PvP on.
static bool is_hostile(Sim& sim, int owner, int target)
{
    Match& match = sim.match;
    return match.state != MATCH_PRACTICE || (sim.fighters[owner].isPvp && sim.fighters[target].isPvp);
}

static bool is_target(Sim& sim, int target, int owner)
{
    if (target >= MAX_FIGHTERS)
    {
        World& world = sim.world;
        int index = target - MAX_FIGHTERS;
        return index < (int)world.dummies.size() &&
               (world.dummies[index].tile < 0 || world.tiles[world.dummies[index].tile] == TILE_BLOCK);
    }
    return target < sim.fighterCount && target != owner && sim.fighters[target].isAlive &&
           is_hostile(sim, owner, target);
}

static Rect target_box(Sim& sim, int target)
{
    return target < MAX_FIGHTERS ? sim.fighters[target].body.box : sim.world.dummies[target - MAX_FIGHTERS].box;
}

// Numbers part way from a level's normal attack to its charged one, damage kept to steps of 5.
static AttackStats stats_blend(const LevelDef& level, float charge)
{
    float damage = math_lerp(level.normal.damage, level.charged.damage, charge);
    return {
        .damage = std::round(damage / DAMAGE_STEP) * DAMAGE_STEP,
        .range = math_lerp(level.normal.range, level.charged.range, charge),
        .speed = math_lerp(level.normal.speed, level.charged.speed, charge),
        .volley = level.normal.volley,
    };
}

// How far a Splitter copy turns from the aim. Copies sit a fixed gap apart, so the fan widens as the Splitter adds
// copies: wide gaps for melee, narrower for thrown weapons, tight for shots, all narrowed by spread (Diazepam). Spins
// share the circle evenly.
static float split_offset(AttackKind kind, int split, int splits, float spread)
{
    if (kind == ATTACK_SPIN)
        return 2 * PI * split / splits;

    float gap = SPLIT_GAP;
    if (kind == ATTACK_SWING || kind == ATTACK_SLASH || kind == ATTACK_POKE || kind == ATTACK_PUNCH ||
        kind == ATTACK_UPPERCUT)
        gap = SPLIT_GAP_MELEE;
    if (kind == ATTACK_BOOMERANG || kind == ATTACK_FLAIL || kind == ATTACK_MINE)
        gap = SPLIT_GAP_THROWN;
    return gap * (split - (splits - 1) / 2.0f) * spread;
}

// Walks from start along angle until range runs out or isBlocked passes, returning where it stopped.
static Vec2 ray_march(Vec2 start, float angle, float range, auto isBlocked)
{
    Vec2 point = start;
    while (vec2_length(point - start) < range && !isBlocked(point))
        point = point + vec2_polar(angle, RAY_STEP);
    return point;
}

// The capsules an attack hits with right now, returning how many. A plain whip fans rays across its cone from the
// hand, out as far ahead as its lash reaches and short of walls. Everything else is one capsule from position to tip.
int shapes_get(Sim& sim, Attack& attack, Capsule* shapes)
{
    if (attack.def()->kind != ATTACK_WHIP || attack.is_charged())
    {
        shapes[0] = {attack.position, attack.tip, attack.radius};
        return 1;
    }
    auto isBlocked = [&](Vec2 point) {
        return sim.world.is_blocking_at(point);
    };
    float front = 0;
    Vec2 forward = vec2_polar(attack.aimAngle, 1);
    for (Vec2 point : lash_get(attack))
        front = std::max(front, vec2_dot(point - attack.origin, forward));
    for (int ray = 0; ray < WHIP_RAYS; ray++)
    {
        float angle = attack.aimAngle + WHIP_CONE * (2.0f * ray / (WHIP_RAYS - 1) - 1);
        shapes[ray] = {attack.origin, ray_march(attack.origin, angle, front, isBlocked), attack.radius};
    }
    return WHIP_RAYS;
}

// Fires the weapon in hand with the given charge if it's ready. Full charge uses the charged attack.
// With the Doubler on, the same attack repeats a moment later for a fraction of the damage (stacked Doublers each
// add a repeat of their own, one after another). With Dual Wield on, an off-hand weapon per copy fires too (see
// Fighter::off_slots_get), each for a fraction of its damage. Every weapon (see Fighter::weapon_key) keeps its own
// cooldown, in any hand, so swapping to another weapon never inherits the last one's wait.
void Weapons::fire(Sim& sim, Fighter& fighter, float charge)
{
    int held = fighter.weapon_key(fighter.slot);
    float gloves = fighter.stat_get(STAT_ATTACK_RATE);
    if (held >= 0 && fighter.cooldowns[held] <= 0 && !is_busy(fighter, held))
    {
        // Its cooldown only starts when something fires (not a continuous weapon already going, nor one at its limit).
        bool isSpawned = is_spawned(sim, fighter, {.charge = charge, .weaponSlot = held});
        fighter.cooldowns[held] = isSpawned ? fighter.level_get(held).cooldown / gloves : 0;
        // Each Doubler copy adds an echo, at its own level's power.
        for (int i = 0, repeat = 0; isSpawned && i < fighter.trinketSlots; i++)
        {
            if (fighter.trinketLoadout[i] != TRINKET_DOUBLER)
                continue;
            float power = TRINKET_DEFS[TRINKET_DOUBLER].levels[fighter.trinketSlotLevels[i]].repeatDamage;
            fighter.echoes.push_back({charge, DOUBLER_DELAY * ++repeat, power, held});
        }
    }

    // Each Dual Wield copy fires one off-hand weapon at its own level's cut, the strongest cut going to the first.
    float powers[SLOT_MAX];
    int copies = 0;
    for (int i = 0; i < fighter.trinketSlots; i++)
        if (fighter.trinketLoadout[i] == TRINKET_DUAL)
            powers[copies++] = TRINKET_DEFS[TRINKET_DUAL].levels[fighter.trinketSlotLevels[i]].offhandDamage;
    std::sort(powers, powers + copies, std::greater<float>());
    int offs[SLOT_MAX];
    int count = fighter.off_slots_get(offs);
    for (int hand = 1; hand <= count; hand++)
    {
        int off = fighter.weapon_key(offs[hand - 1]);
        if (fighter.cooldowns[off] > 0 || is_busy(fighter, off))
            continue;
        bool isSpawned = is_spawned(
            sim, fighter,
            {.charge = charge, .power = powers[hand - 1], .weaponSlot = off, .hand = hand, .isSecondary = true});
        fighter.cooldowns[off] = isSpawned ? fighter.level_get(off).cooldown / gloves : 0;
    }
}

// Whether the fighter's box would fit with its middle at center, clear of walls (and inside the map).
static bool is_box_clear(Sim& sim, Fighter& fighter, Vec2 center)
{
    Rect box = fighter.body.box;
    int columns = (int)(box.w / TELEPORT_PROBE) + 1;
    int rows = (int)(box.h / TELEPORT_PROBE) + 1;
    for (int row = 0; row <= rows; row++)
        for (int column = 0; column <= columns; column++)
        {
            Vec2 point = {center.x - box.w / 2 + box.w * column / columns, center.y - box.h / 2 + box.h * row / rows};
            if (sim.world.is_blocking_at(point))
                return false;
        }
    return true;
}

// Where a teleport toward the cursor lands: the cursor, held within range of the fighter's middle, backed off toward
// the fighter until its box fits there. Returns the fighter's own middle if nowhere fits.
static Vec2 teleport_spot(Sim& sim, Fighter& fighter, Vec2 target, float range)
{
    Vec2 center = fighter.center_get();
    Vec2 offset = target - center;
    float distance = std::min(range, vec2_length(offset));
    Vec2 direction = vec2_normalize(offset);
    for (float along = distance; along > 0; along -= TELEPORT_STEP)
    {
        Vec2 spot = center + direction * along;
        if (is_box_clear(sim, fighter, spot))
            return spot;
    }
    return center;
}

// The fighter's speed along the aim that an inheriting shot gains. Launched fighters lend nothing.
static float push_get(Fighter& fighter, Vec2 aim)
{
    return fighter.isLaunched ? 0 : std::max(0.0f, vec2_dot(fighter.body.velocity, aim));
}

// The damage multiplier a fighter's speed gives an attack fired now along aim, with the Speedometer adding to it.
// Inheriting shots (which gain the part of the fighter's velocity along the aim, so running away never slows them)
// count only that push, everything else the fighter's whole speed.
static float bonus_get(Fighter& fighter, const AttackDef& def, Vec2 aim)
{
    float speed = def.isInheriting ? push_get(fighter, aim) : vec2_length(fighter.body.velocity);
    return 1 + (SPEED_DAMAGE + fighter.stat_get(STAT_SPEED_DAMAGE)) * speed / SPEED_UNIT;
}

// How much a fighter's color fills in from the bonus its held weapon would get firing right now.
float Weapons::buff_get(Fighter& fighter)
{
    int held = fighter.weapon_get();
    if (held < 0)
        return 0;
    return fill_get(bonus_get(fighter, WEAPON_DEFS[held].attack_get(variant_get(fighter.charge)), fighter.aim));
}

// What an attack does for this fighter, mirroring is_spawned and damage_deal: Splitter copies hit for less and come
// out smaller, Embiggener adds damage, Gloves and Energy Drink speed up attacking and charging, Enlarger grows blasts
// and melee reach, the Accelerator speeds up projectiles (and so, like the Hourglass, carries timed shots further),
// Diazepam tightens spread and Shock Absorber eases lunges.
// "Every" is the cooldown, or for a charged attack the time to charge.
AttackSummary attack_summary_get(Fighter& fighter, int weapon, int level, AttackVariant variant)
{
    const WeaponDef& def = WEAPON_DEFS[weapon];
    const AttackDef& attack = variant == VARIANT_CHARGED ? def.charged : def.normal;
    const LevelDef& levelDef = def.levels[level];
    AttackStats stats = variant == VARIANT_CHARGED ? levelDef.charged : levelDef.normal;
    AttackKind kind = attack.kind;
    bool isTeleport = kind == ATTACK_TELEPORT;
    int splits = isTeleport ? 1 : (int)fighter.stat_get(STAT_COPIES);
    float splitScale = splits > 1 ? SPLIT_SCALE : 1;
    float embiggen = fighter.stat_get(STAT_DAMAGE);
    float enlarger = fighter.stat_get(STAT_ATTACK_SIZE);
    float gloves = fighter.stat_get(STAT_ATTACK_RATE);
    float drink = fighter.stat_get(STAT_CHARGE_RATE);
    float accelerator = attack.isProjectile ? fighter.stat_get(STAT_PROJECTILE_SPEED) : 1;
    float steadiness = 1 - fighter.stat_get(STAT_SPREAD_CUT);
    float absorb = fighter.stat_get(STAT_MOVEMENT);

    AttackSummary summary;
    summary.isDamaging = kind != ATTACK_DETONATE && stats.damage > 0;
    float damage =
        splits > 1 ? std::max(1.0f, std::round(stats.damage * fighter.stat_get(STAT_COPY_DAMAGE))) : stats.damage;
    summary.damage = std::round(damage * embiggen);
    summary.isDamageChanged = summary.damage != stats.damage;
    summary.every = variant == VARIANT_CHARGED ? CHARGE_TIME / drink : levelDef.cooldown / gloves;
    summary.isEveryChanged = variant == VARIANT_CHARGED ? drink != 1 : gloves != 1;
    float flight = is_aging(attack, stats) ? accelerator * fighter.stat_get(STAT_LIFETIME) : 1;
    float reach = reach_get(attack.path, stats);
    summary.range = reach * (attack.isRigid ? enlarger * splitScale : flight);
    summary.isRangeChanged = summary.range != reach;
    summary.area = stats.area * attack.scale * enlarger * splitScale;
    summary.isAreaChanged = enlarger != 1 || splits > 1;
    summary.speed = attack.isProjectile ? stats.speed * accelerator : 0;
    summary.isSpeedChanged = accelerator != 1;
    summary.spread = attack.spread * steadiness;
    summary.isSpreadChanged = steadiness != 1;
    summary.lunge = stats.lunge * absorb;
    summary.isLungeChanged = absorb != 1;
    summary.pieces = stats.volley * splits;
    summary.isPiecesChanged = splits > 1;
    // A detonator only sets off what's already out: one press, nothing of its own.
    if (kind == ATTACK_DETONATE)
    {
        summary.range = summary.area = summary.speed = 0;
        summary.pieces = 1;
        summary.isPiecesChanged = false;
    }
    if (levelDef.limit > 0 && variant != VARIANT_CHARGED)
        summary.out = levelDef.limit;
    else if (kind == ATTACK_BOOMERANG || kind == ATTACK_MINE)
        summary.out = levelDef.count;
    return summary;
}

// Builds and launches a weapon's attack, reporting whether anything fired. Every attack leaves a little off the aim, by
// as much as its spread, which Diazepam steadies. Every fighter hits harder the faster it's moving (or, for
// shots, the faster it moves along the aim), and the Speedometer adds to that. Trinkets speed up projectiles and grow
// attacks here. Detonating sets off the weapon's mines instead, and mines won't place past the level's count. A level
// with a limit fires only as many pieces as fit under it (see LevelDef).
bool Weapons::is_spawned(Sim& sim, Fighter& fighter, Shot shot)
{
    int key = shot.weaponSlot;
    int held = fighter.weaponLoadout[key];
    float charge = shot.charge;
    float power = shot.power;
    const WeaponDef& weapon = WEAPON_DEFS[held];
    const LevelDef& level = fighter.level_get(key);
    AttackVariant variant = variant_get(charge);
    const AttackDef& def = variant == VARIANT_CHARGED ? weapon.charged : weapon.normal;
    AttackStats stats = variant == VARIANT_CHARGED ? level.charged : level.normal;
    if (weapon.mode == FIRE_DRAWN)
        stats = stats_blend(level, charge);

    AttackKind kind = def.kind;
    int mines = 0;
    for (Attack& attack : attacks)
        mines += attack.def()->kind == ATTACK_MINE && attack.owner == fighter.index && attack.key == key &&
                 !attack.isDead && !attack.isCopy;
    if (kind == ATTACK_MINE && !shot.isEcho && mines >= level.count)
        return false;
    if (level.limit > 0 && !shot.isSecondary)
    {
        int out = 0;
        for (Attack& attack : attacks)
            out += attack.def() == &def && attack.owner == fighter.index && attack.key == key && !attack.isCopy &&
                   !attack.isSecondary && !attack.isDead;
        if (out >= level.limit)
            return false;
        stats.volley = std::min(stats.volley, level.limit - out);
    }

    // A continuous weapon only ever has one attack going from a hand (which keeps itself going while held), so firing
    // it again does nothing.
    bool isContinuing = weapon.mode == FIRE_CONTINUOUS && variant != VARIANT_CHARGED && !shot.isEcho;
    if (isContinuing && continuous_get(fighter, key, shot.hand))
        return false;
    if (!shot.isSecondary)
    {
        fighter.kickFrom = weapon.kick;
        fighter.kickTo = weapon.follow;
        fighter.kickTime = 0;
    }
    if (kind == ATTACK_DETONATE)
    {
        // With nothing armed to set off, the detonator just clicks.
        bool isLive = false;
        for (Attack& attack : attacks)
        {
            if (!is_armed(attack) || attack.owner != fighter.index || attack.key != key || attack.isDead)
                continue;
            attack_explode(sim, attack);
            isLive = true;
        }
        sim.cues->sound_play(isLive ? def.sound : SOUND_DETONATE_EMPTY);
        return true;
    }

    float hourglass = is_aging(def, stats) ? fighter.stat_get(STAT_LIFETIME) : 1;
    float lifetime = lifetime_get(def, stats) * hourglass;
    float accelerator = def.isProjectile ? fighter.stat_get(STAT_PROJECTILE_SPEED) : 1;
    stats.speed *= accelerator;
    // A rope or chain is as long as its shot's flight carries it, so it lengthens as the flight does.
    if (def.isTethered)
        stats.range *= hourglass * accelerator;
    float spread = 1 - fighter.stat_get(STAT_SPREAD_CUT);
    float jitter = def.spread * DEGREE * spread;
    Vec2 aim = vec2_polar(vec2_angle(fighter.aim) + sim.rng.random_get(-jitter, jitter), 1);
    float push = def.isInheriting ? push_get(fighter, aim) : 0;
    // A part-charged normal attack (not one whose charge already strengthens it its own way) adds to the speed bonus,
    // so it hits harder and fills in, glows and shakes the same way.
    float bonus = bonus_get(fighter, def, aim);
    if (variant != VARIANT_CHARGED && !weapon.isChargeScaled)
        bonus *= 1 + charge * PARTIAL_CHARGE_BONUS;
    stats.damage = std::max(1.0f, std::round(stats.damage * power * bonus));

    Attack attack = {
        .stats = stats,
        .origin = fighter.hand_get(shot.hand),
        .velocity = aim * stats.speed,
        .aimAngle = vec2_angle(aim),
        .angle = vec2_angle(aim),
        .bonus = bonus,
        .duration = def.duration,
        .fade = stats.fade > 0 ? stats.fade * hourglass : lifetime,
        .lifetime = lifetime,
        .scale = def.scale * stats.scale,
        .bounces = def.isBouncy ? (int)fighter.stat_get(STAT_RICOCHETS) : 0,
        .hitsLeft = def.hits,
        .owner = fighter.index,
        .weapon = held,
        .key = key,
        .hand = shot.hand,
        .variant = variant,
        .isLeft = fighter.is_left(),
        .isSecondary = shot.isSecondary,
    };
    attack.position = muzzle_get(attack);

    // Charging burns a grenade's fuse down (fully charged, it goes off in the barrel, see below).
    if (kind == ATTACK_GRENADE)
        attack.lifetime = std::max(TICK, attack.lifetime * (1 - charge));

    // A teleport is one spell however many copies anything else would make: it marks where it will land.
    if (kind == ATTACK_TELEPORT)
    {
        attack.position = teleport_spot(sim, fighter, fighter.controls.cursor, stats.range);
        attack.origin = fighter.center_get();
        attack.tip = attack.position;
        attack.hitsLeft = 0;
        attack.scale *= fighter.stat_get(STAT_ATTACK_SIZE);
        attack.isCopy = shot.isEcho;
        attack_remember(attack);
        attacks.push_back(attack);
        sim.cues->sound_play(shot.isEcho ? SOUND_ECHO : def.sound);
        return true;
    }

    if (kind == ATTACK_UPPERCUT)
        attack.angle -= (fighter.is_left() ? -1 : 1) * PI / 2;
    attack.scale *= fighter.stat_get(STAT_ATTACK_SIZE);

    int splits = fighter.stat_get(STAT_COPIES);
    if (splits > 1)
    {
        attack.scale *= SPLIT_SCALE;
        attack.stats.damage = std::max(1.0f, std::round(attack.stats.damage * fighter.stat_get(STAT_COPY_DAMAGE)));
    }

    // A rigid attack reaches as far as it has grown or shrunk (Enlarger, Splitter). A Vacuum pulls and blows only as
    // hard as the shot's power (Doubler repeats, off hands).
    if (def.isRigid)
        attack.stats.range *= attack.scale / (def.scale * stats.scale);
    if (is_cone(def))
        attack.stats.speed *= power;

    // One piece per volley shot per split, each fanned around the aim (or set side by side when the volley has no
    // fan). The center split stays primary and the rest are secondary.
    for (int v = 0; v < stats.volley; v++)
    {
        float place = stats.volley > 1 ? (float)v / (stats.volley - 1) - 0.5f : 0;
        for (int split = 0; split < splits; split++)
        {
            float offset = 0;
            if (stats.volley > 1)
                offset += (stats.fan * place + sim.rng.random_get(-def.scatter, def.scatter) * DEGREE) * spread;
            if (splits > 1)
                offset += split_offset(kind, split, splits, spread);

            Attack piece = attack;
            if (stats.fan <= 0)
                piece.origin =
                    piece.origin + vec2_polar(attack.angle + PI / 2, VOLLEY_GAP * (stats.volley - 1) * place);
            piece.angle += offset;
            piece.aimAngle += offset;
            piece.velocity = vec2_polar(piece.angle, stats.speed + push);
            // A slash sets off a little ahead of the hand, clear of its fighter.
            float slash = SLASH_DISTANCE * piece.scale + SLASH_GAP;
            piece.position = kind == ATTACK_SLASH ? piece.origin + vec2_polar(piece.angle, slash) : muzzle_get(piece);
            piece.isSecondary |= split != splits / 2;
            piece.isCopy = shot.isEcho || split != splits / 2;
            if (def.isOrbiting)
            {
                // Wisps rise out of the fighter's middle to join its orbit (see orbits_update). Cast with attack held
                // they gather there until it's let go (see orbits_release); otherwise each sets off a little after the
                // last.
                int index = v * splits + split;
                piece.isGathering = fighter.is_down(CONTROL_ATTACK);
                piece.slot = index;
                piece.duration = attack.duration + index * WISP_LAUNCH_STAGGER;
                piece.position = fighter.center_get();
                piece.orbit = {};
                piece.velocity = {};
                // Until it sets off, its angle is only how far its spread (and any split) turns it off the aim.
                piece.angle = std::remainder(piece.aimAngle - vec2_angle(fighter.aim), 2 * PI);
            }
            // A fully charged grenade never leaves the barrel: it goes off right there, with no grenade to clonk anyone
            // first.
            if (kind == ATTACK_GRENADE && variant == VARIANT_CHARGED)
            {
                attack_explode(sim, piece);
                continue;
            }
            if (def.isInstant)
                instant_launch(sim, piece);
            if (kind == ATTACK_WHIP)
                whip_pull(sim, piece);
            attacks.push_back(piece);
        }
    }
    sim.cues->sound_play(shot.isEcho ? SOUND_ECHO : def.sound);

    float side = fighter.is_left() ? -1 : 1;
    if (weapon.flash > 0)
        sim.cues->flash_spawn(attack, weapon.flash);
    if (weapon.isEjecting)
        sim.cues->burst_spawn(CASING_BURST, attack.origin, vec2_angle(aim) - side * (PI / 2 + CASING_BACK),
                              fighter.index);
    if (variant == VARIANT_CHARGED)
        sim.cues->shake_add(def.shake * FIRE_SHAKE);

    // An uppercut launches its fighter the way it rises, canceling any speed against that first. Shock Absorber
    // softens every push the shot gives its own fighter: lunges, kickback and Recoil Coil.
    float absorb = fighter.stat_get(STAT_MOVEMENT);
    Vec2 lunge = kind == ATTACK_UPPERCUT ? vec2_polar(attack.angle, 1) : aim;
    if (kind == ATTACK_UPPERCUT)
        fighter.body.velocity = fighter.body.velocity - lunge * std::min(0.0f, vec2_dot(fighter.body.velocity, lunge));
    if (stats.lunge > 0)
        fighter.burst_add(lunge * stats.lunge * absorb);
    if (stats.lunge < 0)
        fighter.impulse_add(aim * stats.lunge * absorb);
    float recoil = fighter.stat_get(STAT_RECOIL) * math_pow(stats.damage * stats.volley, RECOIL_CURVE) * absorb;
    if (recoil > 0)
        fighter.impulse_add(fighter.aim * -recoil);
    return true;
}

void Weapons::update(Sim& sim)
{
    for (int i = 0; i < sim.fighterCount; i++)
        contact_update(sim, sim.fighters[i]);
    for (int i = 0; i < sim.fighterCount; i++)
    {
        Fighter& fighter = sim.fighters[i];
        if (fighter.hitstop > 0)
            continue;
        if (fighter.isAlive)
            sim.cues->fighter_aura_spawn(fighter);
        for (Echo& echo : fighter.echoes)
        {
            echo.timer -= TICK;
            if (echo.timer <= 0 && echo.weaponSlot == fighter.weapon_key(fighter.slot))
                is_spawned(sim, fighter,
                           {
                               .charge = echo.charge,
                               .power = echo.power,
                               .weaponSlot = echo.weaponSlot,
                               .isEcho = true,
                               .isSecondary = true,
                           });
        }
        fighter.echoes.erase_if([](Echo& echo) { return echo.timer <= 0; });
    }

    orbits_update(sim);

    // A fighter's attacks freeze with it in hitstop.
    for (Attack& attack : attacks)
    {
        if (sim.fighters[attack.owner].hitstop > 0)
        {
            attack_remember(attack);
            continue;
        }
        bool isNew = attack.time == 0;
        attack_remember(attack);
        attack_move(sim, attack);
        if (isNew)
            attack_remember(attack);
        attack.hitCooldown -= TICK;
        AttackKind kind = attack.def()->kind;
        bool isResting = (attack.velocity.x == 0 && attack.velocity.y == 0) || kind == ATTACK_FLAME;
        bool isLine = kind == ATTACK_BEAM || kind == ATTACK_WHIP;
        bool isAir = is_cone(*attack.def());
        if (!isLine && !isAir && kind != ATTACK_EXPLOSION && !attack.isAttached && !isResting)
            sim.cues->attack_afterimage_spawn(attack);
        if (!attack.isAttached && !isAir)
            sim.cues->attack_aura_spawn(attack);

        // Dummies and blocks are checked before fighters, so racers crowding a block can't soak up every swing at it.
        Capsule shapes[WHIP_RAYS];
        int shapeCount = shapes_get(sim, attack, shapes);
        int targets = MAX_FIGHTERS + sim.world.dummies.size();
        for (int i = 0; i < targets; i++)
        {
            int target = (i + MAX_FIGHTERS) % targets;
            bool isStruck = target < STRUCK_MAX && (attack.struck >> target & 1);
            if (attack.hitsLeft <= 0 || attack.hitCooldown > 0 || isStruck || !is_target(sim, target, attack.owner))
                continue;
            for (int shape = 0; shape < shapeCount; shape++)
            {
                Vec2 point;
                if (!is_capsule_in_rect(shapes[shape], target_box(sim, target), point))
                    continue;
                attack_hit(sim, attack, target, point);
                break;
            }
        }
        attack.time += TICK;
    }
    tesla_update(sim);
    attacks_cap(sim);
    std::erase_if(attacks, [](Attack& attack) { return attack.isDead; });
    attacks.insert(attacks.end(), pending.begin(), pending.end());
    pending.clear();
}

// No fighter keeps more than ATTACKS_MAX attacks out: past that, their oldest loose ones (anything not anchored to the
// fighter, not the weapon itself out of the hand and not an explosion going off, so mines, stuck arrows, wisps and
// flames) fizzle out with a puff, oldest first. Attacks are kept in the order they were made, so the first found are
// the oldest.
void Weapons::attacks_cap(Sim& sim)
{
    for (int i = 0; i < sim.fighterCount; i++)
    {
        int count = 0;
        for (Attack& attack : attacks)
            count += attack.owner == i && !attack.isDead;
        for (Attack& attack : attacks)
        {
            if (count <= ATTACKS_MAX)
                break;
            const AttackDef& def = *attack.def();
            bool isHeld = def.anchor != ANCHOR_WORLD || def.isWielded || def.kind == ATTACK_EXPLOSION;
            if (attack.owner != i || attack.isDead || isHeld)
                continue;
            attack.isDead = true;
            count--;
            sim.cues->attack_burst_spawn(SMOKE_BURST, attack.position, 0, attack);
        }
    }
}

// Advances an attack by one tick according to its kind and updates its hit capsule.
void Weapons::attack_move(Sim& sim, Attack& attack)
{
    const AttackDef& def = *attack.def();
    Fighter& fighter = sim.fighters[attack.owner];
    float progress = attack.progress_get();
    float range = attack.stats.range;
    attack.radius = def.shape == SHAPE_CIRCLE ? attack.stats.range : def.radius * attack.scale;
    attack.hitsLeft = def.isInstant && attack.time > 0 ? 0 : attack.hitsLeft;
    if (def.anchor != ANCHOR_WORLD)
        path_move(sim, attack);
    else if (def.path != PATH_OWN)
        flight_move(sim, attack);

    // A mine, flail ball or grapple left out goes once its slot no longer holds the weapon that put it there (which
    // could no longer set it off, reel it in or let it go), a mine fizzling with a puff.
    bool isLeftOut = def.isArming || def.isTethered;
    if (isLeftOut && !attack.isExplosion && fighter.weaponLoadout[attack.key] != attack.weapon)
    {
        attack.isDead = true;
        if (def.isArming)
            sim.cues->attack_burst_spawn(SMOKE_BURST, attack.position, 0, attack);
        return;
    }

    switch (def.kind)
    {
        case ATTACK_SWING:
        {
            // The head sweeps its arc overhead (see path_move).

            // A head striking a wall stops the swinger's motion along the aim and boosts them back against it (aiming
            // down at the floor pops them up), once per swing.
            if (!attack.isRebounded && sim.world.is_blocking_at(attack.position))
            {
                Vec2 away = vec2_polar(attack.aimAngle + PI, 1);
                float into = vec2_dot(fighter.body.velocity, away);
                fighter.body.velocity = fighter.body.velocity - away * std::min(0.0f, into);
                fighter.impulse_add(away * HAMMER_REBOUND * (attack.is_charged() ? HAMMER_REBOUND_CHARGED : 1) *
                                    fighter.stat_get(STAT_MOVEMENT));
                attack.isRebounded = true;
                sim.cues->sound_play(SOUND_BOUNCE);
                sim.cues->burst_spawn(IMPACT_BURST, attack.position, 0, attack.owner);
            }
            if (!attack.isDead || !attack.is_charged())
                break;
            attack.radius = range * SLAM_RATIO;
            sim.cues->sound_play(SOUND_SLAM);
            sim.cues->shake_add(def.shake);
            sim.cues->burst_spawn(SLAM_BURST, attack.position, 0, attack.owner);
            break;
        }
        case ATTACK_PUNCH:
            break;
        case ATTACK_UPPERCUT:
        {
            // The fist rises beside its fighter on the aimed side, carried up with them. Splitter's smaller copies
            // keep the full reach so they fan out around the fighter instead of piling up on it.
            float reach = UPPERCUT_REACH * attack.scale;
            if (fighter.stat_get(STAT_COPIES) > 1)
                reach /= SPLIT_SCALE;
            attack.position = attack.origin + vec2_polar(attack.aimAngle, reach);
            break;
        }
        case ATTACK_POKE:
        {
            // Its path carries the tip, never closer in than the lance's own length, so the whole lance stays out in
            // front of the hand and a bigger one reaches no further.
            float shaft = LANCE_LENGTH * attack.scale;
            float along = std::max(shaft, vec2_length(attack.position - attack.origin));
            attack.tip = attack.origin + vec2_polar(attack.angle, along);
            attack.position = attack.tip - vec2_polar(attack.angle, shaft);
            if (attack.is_charged() && progress < PATH_OUT)
                sim.cues->burst_spawn(TRAIL_BURST, attack.tip, attack.angle + PI, attack.owner);
            break;
        }
        case ATTACK_ROCKET:
            sim.cues->burst_spawn(SMOKE_BURST, attack.position - vec2_polar(attack.angle, ROCKET_TAIL),
                                  attack.angle + PI, attack.owner);
            break;
        case ATTACK_TELEPORT:
            teleport_move(sim, attack);
            break;
        case ATTACK_DETONATE:
            break;
        case ATTACK_EXPLOSION:
            attack.isDead = progress >= 1;
            break;
        case ATTACK_BEAM:
            // A beam hits only as it's fired, then fades where it was: its first stretch stays strung from the hand
            // to where it struck, and each stretch it ricocheted along stays where it bounced.
            attack.isDead = progress >= 1;
            if (attack.ricochets == 0)
            {
                attack.origin = fighter.hand_get(attack.hand);
                attack.angle = vec2_angle(attack.tip - attack.origin);
                attack.position = attack.origin + vec2_polar(attack.angle, WHIP_HANDLE);
            }
            break;
        case ATTACK_WHIP:
        {
            // A charged crack stays strung from the end of the handle in the hand to where it cracked, hitting at
            // once. A plain lash goes with the hand, as long as its reach along the aim (short of any wall), its handle
            // and links moving as lash_get says. It hits anywhere in its cone as far as it reaches until it cracks.
            if (attack.is_charged())
            {
                attack.origin = fighter.hand_get(attack.hand);
                attack.isDead = progress >= 1;
                attack.angle = vec2_angle(attack.tip - attack.origin);
                attack.position = attack.origin + vec2_polar(attack.angle, WHIP_HANDLE);
                break;
            }
            auto isBlocked = [&](Vec2 point) {
                return sim.world.is_blocking_at(point);
            };
            Vec2 reach = ray_march(attack.origin, attack.aimAngle, reach_at_get(attack), isBlocked);
            attack.angle = vec2_angle(lash_direction_get(attack, lash_heading_get(progress)));
            attack.position = attack.origin + vec2_polar(attack.angle, WHIP_HANDLE);
            attack.length = std::max(0.0f, vec2_length(reach - attack.origin) - WHIP_HANDLE);
            attack.tip = lash_get(attack).back();
            attack.hitsLeft = progress < PATH_OUT ? attack.hitsLeft : 0;
            break;
        }
        case ATTACK_SPIN:
        {
            // Keeps circling its arc while attack is held, whooshing each lap. Let go, its lifetime ends with the lap.
            int hand = fighter.hand_slot_get(attack.hand);
            bool isHeld = fighter.is_down(CONTROL_ATTACK) && hand >= 0 && fighter.weapon_key(hand) == attack.key;
            float lap = 2 * PI * range / attack.stats.speed;
            float laps = std::floor(attack.life_get() / lap);
            if (isHeld && laps > std::floor((attack.life_get() - TICK) / lap))
                sim.cues->sound_play(def.sound);
            if (!isHeld)
                attack.lifetime = std::min(attack.lifetime, (laps + 1) * lap);
            break;
        }
        case ATTACK_MINE:
            // Armed, it blinks, quicker (and beeping) as the end of its lifetime nears.
            attack.blink -= is_armed(attack) ? TICK : 0;
            if (attack.blink <= 0 && is_armed(attack))
            {
                attack.blink = mine_blink_get(attack);
                if (attack.life_get() > attack.lifetime - MINE_HURRY)
                    sim.cues->sound_play(SOUND_BEEP);
            }
            break;
        case ATTACK_VACUUM:
            vacuum_move(sim, attack);
            break;
        case ATTACK_GUST:
            gust_move(sim, attack);
            break;
        default:
            break;
    }

    // A flying shot's hitbox already spans its path this tick, and pokes, beams and lashes reach their own tips.
    bool isFlying = def.anchor == ANCHOR_WORLD && def.path != PATH_OWN;
    if (!isFlying && def.kind != ATTACK_POKE && def.kind != ATTACK_BEAM && def.kind != ATTACK_WHIP)
        attack.tip = attack.position;
    attack.isHeld = false;
}

// Places an anchored attack along its path from its anchor (its fighter's hand or middle) for its age, ending it once
// its lifetime is up: as far out along its heading as its speed has carried it (an eased one speeding up as it goes),
// out and back, or as far round its arc. One moved by its own code (a Vacuum's cone) just stays at the muzzle along its
// fighter's aim, keeping whatever turn it set off with (a Splitter copy's place in the fan), its own code ending it.
void Weapons::path_move(Sim& sim, Attack& attack)
{
    const AttackDef& def = *attack.def();
    Fighter& fighter = sim.fighters[attack.owner];
    if (def.path == PATH_OWN)
    {
        if (attack.time == 0)
            attack.angle = attack.aimAngle - vec2_angle(fighter.aim);
        attack.aimAngle = vec2_angle(fighter.aim) + attack.angle;
        attack.origin = def.anchor == ANCHOR_HAND ? fighter.hand_get(attack.hand) : fighter.center_get();
        attack.position = attack.origin + vec2_polar(attack.aimAngle, MUZZLE_DISTANCE);
        attack.tip = attack.position + vec2_polar(attack.aimAngle, cone_reach_get(attack));
        return;
    }
    float age = attack.life_get();
    float out = PATH_OUT * attack.lifetime;
    float travel = def.isEased ? age * age / attack.lifetime : age;
    if (def.path == PATH_RETURN && age > out)
        travel = std::max(0.0f, out * (attack.lifetime - age) / (attack.lifetime - out));
    float distance = attack.stats.speed * travel;
    if (def.path == PATH_ARC)
    {
        attack.angle = attack.aimAngle + (attack.isLeft ? -1 : 1) * (ARC_START + distance / attack.stats.range);
        distance = attack.stats.range;
    }
    attack.origin = def.anchor == ANCHOR_HAND ? fighter.hand_get(attack.hand) : fighter.center_get();
    attack.position = attack.origin + vec2_polar(attack.angle, distance);
    attack.isDead = age >= attack.lifetime;
}

// Which way is off the surface a bolt landed on at wall, coming from where it is: a slope's own normal, or else the
// side of the wall it ran into.
static Vec2 surface_normal_get(Sim& sim, Vec2 from, Vec2 wall)
{
    Vec2 normal = sim.world.normal_get(wall);
    if (normal.x != 0 || normal.y != 0)
        return vec2_normalize(normal);
    if (sim.world.is_blocking_at({from.x, wall.y}))
        return {0, wall.y > from.y ? -1.0f : 1.0f};
    return {wall.x > from.x ? -1.0f : 1.0f, 0};
}

// Flies a free shot one tick under its physics: turning toward its fighter's cursor (homing), speeding up toward its
// top speed, slowing with drag and falling (or rising) with gravity, unless a Vacuum holds it, then moving in small
// steps so it can't skip through a thin wall (its hitbox spanning the whole step so it can't skip past targets either)
// until it touches one (see wall_hit). A bouncing shot moves as a small body instead, a passing one straight through,
// and a crawling one on a surface crawls along it. Its lifetime up, it bursts, or fizzles out.
void Weapons::flight_move(Sim& sim, Attack& attack)
{
    const AttackDef& def = *attack.def();
    Vec2 start = attack.position;
    Fighter& fighter = sim.fighters[attack.owner];
    // An orbiting shot glides to its place in its fighter's orbit and circles with it until its moment comes, then
    // sets off toward wherever the cursor is right then (plus its spread), its flight starting from there.
    if (def.isOrbiting && (attack.isGathering || attack.time < attack.duration))
    {
        Vec2 place = vec2_polar(attack.orbitAngle, attack.orbitRadius);
        attack.orbit = attack.orbit + (place - attack.orbit) * std::min(1.0f, WISP_GLIDE * TICK);
        attack.position = fighter.center_get() + attack.orbit;
        attack.origin = attack.position;
        attack.lifeStart = attack.time;
        attack.tip = attack.position;
        return;
    }
    if (def.isOrbiting && attack.velocity.x == 0 && attack.velocity.y == 0)
    {
        attack.angle += vec2_angle(fighter.controls.cursor - attack.position);
        attack.velocity = vec2_polar(attack.angle, attack.stats.speed);
        sim.cues->sound_play(SOUND_WISP);
    }
    attack.isReturning |= def.path == PATH_RETURN && attack.time >= attack.restTime + def.hold;
    if (attack.isReturning && def.isTethered)
        attack.isDead = is_caught(fighter, attack);
    else if (attack.isReturning)
        attack.isDead = shot_return(sim, fighter, attack);
    else if (attack.isAttached && def.wall == WALL_CRAWL)
        crawl_move(sim, attack);
    else if (!attack.isAttached)
    {
        float speed = vec2_length(attack.velocity);
        Vec2 toward = fighter.controls.cursor - attack.position;
        if (def.homing > 0 && speed > 0 && vec2_length(toward) > HOMING_MIN)
        {
            float heading = vec2_angle(attack.velocity);
            float turn = std::remainder(vec2_angle(toward) - heading, 2 * PI);
            attack.velocity = vec2_polar(heading + std::clamp(turn, -def.homing * TICK, def.homing * TICK), speed);
        }
        if (def.accelerate > 0 && speed > 0)
            attack.velocity = vec2_normalize(attack.velocity) *
                              std::min(attack.stats.speed * def.speedup, speed + def.accelerate * TICK);
        attack.velocity = attack.velocity * def.drag;
        attack.velocity.y += attack.isHeld ? 0 : def.gravity * TICK;
        // An arming shot (or one going out and back) slowed to a crawl comes to rest, arming (or waiting to head back)
        // from then. Once rested, it only drifts.
        bool isResting = def.isArming || def.path == PATH_RETURN;
        if (isResting && std::isinf(attack.restTime) && vec2_length(attack.velocity) < REST_SPEED)
        {
            attack.velocity = {};
            attack.restTime = attack.time;
        }
        if (def.isAligned && (attack.velocity.x != 0 || attack.velocity.y != 0))
            attack.angle = vec2_angle(attack.velocity);
        // A tethered shot pulls up short at the end of its chain.
        Vec2 hand = fighter.hand_get(attack.hand);
        Vec2 offset = attack.position + attack.velocity * TICK - hand;
        if (def.isTethered && vec2_length(offset) > attack.stats.range)
            attack.velocity = (hand + vec2_normalize(offset) * attack.stats.range - attack.position) * (1 / TICK);

        Vec2 next = attack.position + attack.velocity * TICK;
        Vec2 wall;
        WallCheck isWall = def.isPassingPlatforms ? &World::is_solid_at : &World::is_blocking_at;
        if (def.wall == WALL_BOUNCE)
            body_bounce(sim, attack);
        else if (def.wall == WALL_PASS && attack.bounces <= 0)
            attack.position = next;
        else if (is_wall_reached(sim, attack, next, wall, isWall))
            wall_hit(sim, attack, wall, attack.isHeld);
    }
    attack.tip = start;

    bool isOver = !attack.isDead && attack.life_get() >= attack.lifetime;
    if (isOver && def.isBursting)
        attack_explode(sim, attack);
    else if (isOver)
    {
        attack.isDead = true;
        if (def.wall == WALL_END)
            sim.cues->burst_spawn(IMPACT_BURST, attack.position, 0, attack.owner);
    }
}

// A flying shot touching a wall: held in a Vacuum, it glances off. Otherwise Ricochet bounces it while it has bounces
// left, and then its wall response decides: it ends (with a thud), bursts, sticks and lingers (harmless, as a foothold
// for its fighter, though a breakable block just takes the hit), settles against the surface to crawl along it the way
// it was going, or stops dead.
void Weapons::wall_hit(Sim& sim, Attack& attack, Vec2 wall, bool isHeld)
{
    const AttackDef& def = *attack.def();
    if (isHeld)
    {
        attack.velocity = reflect_get(sim, attack.position, wall, attack.velocity);
        return;
    }
    if (attack.bounces > 0)
    {
        ricochet(sim, attack, wall);
        return;
    }
    bool isBlock = sim.world.tile_at(wall) == TILE_BLOCK;
    switch (def.wall)
    {
        case WALL_STICK:
            if (!isBlock)
            {
                attack.isAttached = true;
                attack.hitsLeft = 0;
                attack.velocity = {};
                attack.lifetime = attack.life_get() + ARROW_LINGER;
                impact_play(sim, def.kind);
                sim.cues->burst_spawn(IMPACT_BURST, wall, 0, attack.owner);
                break;
            }
            [[fallthrough]];
        case WALL_END:
            attack.isDead = true;
            impact_play(sim, def.kind);
            sim.cues->burst_spawn(IMPACT_BURST, attack.position, 0, attack.owner);
            break;
        case WALL_BURST:
            attack.position = wall;
            attack_explode(sim, attack);
            break;
        case WALL_CRAWL:
        {
            Vec2 normal = surface_normal_get(sim, attack.position, wall);
            Vec2 along = {-normal.y, normal.x};
            along = vec2_dot(attack.velocity, along) < 0 ? along * -1 : along;
            for (float reach = 0; reach < CRAWL_SNAP && !sim.world.is_blocking_at(attack.position - normal); reach++)
                attack.position = attack.position - normal;
            attack.side = along.x * -normal.y - along.y * -normal.x > 0 ? 1 : -1;
            attack.velocity = along * attack.stats.speed;
            attack.isAttached = true;
            break;
        }
        case WALL_LATCH:
            attack.position = wall;
            hook_attach(sim, attack);
            break;
        case WALL_RETURN:
            attack.isReturning = true;
            sim.cues->burst_spawn(IMPACT_BURST, attack.position, 0, attack.owner);
            [[fallthrough]];
        case WALL_STOP:
        case WALL_BOUNCE:
        case WALL_PASS:
            attack.velocity = {};
            impact_play(sim, def.kind);
            break;
    }
}

// A crawling shot on a surface: each step it turns as far toward its surface as it can still move, from straight into
// it round to straight away from it, so it hugs floors, walls, ceilings, platforms, corners and edges alike, at its
// speed. Boxed in, it turns back. One left inside a wall (fired from in one) fizzles out.
void Weapons::crawl_move(Sim& sim, Attack& attack)
{
    float speed = attack.stats.speed;
    int steps = std::max(1, (int)(speed * TICK / CRAWL_STEP));
    for (int step = 0; step < steps; step++)
    {
        float heading = vec2_angle(attack.velocity);
        bool isMoved = false;
        for (int turn = 0; turn <= CRAWL_TURNS && !isMoved; turn++)
        {
            float angle = heading + attack.side * (PI / 2 - turn * PI / CRAWL_TURNS);
            Vec2 ahead = attack.position + vec2_polar(angle, CRAWL_STEP);
            if (sim.world.is_blocking_at(ahead))
                continue;
            attack.position = ahead;
            attack.velocity = vec2_polar(angle, speed);
            isMoved = true;
        }
        if (!isMoved)
            attack.velocity = attack.velocity * -1;
    }
    attack.angle = vec2_angle(attack.velocity);
    attack.isDead |= sim.world.is_blocking_at(attack.position);
}

// A bouncing shot moves as a small box body, staying on the ground across ramps the way a fighter does (stepping over
// a ramp's crest and down its far side). Off surfaces it bounces back (with a knock), losing some speed, slanting off
// ramps. On the ground it rolls downhill under its gravity, and on the flat to a stop, turning as it goes. A bounce
// Ricochet counts starts its flight afresh, as a ricochet does any shot's.
void Weapons::body_bounce(Sim& sim, Attack& attack)
{
    const AttackDef& def = *attack.def();
    float size = def.body * attack.scale;
    Body body = {
        .box = {attack.position.x - size / 2, attack.position.y - size / 2, size, size},
        .velocity = attack.velocity,
        .slope = attack.slope,
        .isGrounded = attack.isGrounded,
    };
    if (body.isGrounded)
        body.velocity.x += def.gravity * body.slope / (1 + body.slope * body.slope) * TICK;
    Vec2 before = body.velocity;
    sim.world.body_move(body);
    bool isBounced = false;
    bool isRamp = body.normal.x != 0 || body.normal.y != 0;
    float into = vec2_dot(before, body.normal);
    if (isRamp && into < -SHOT_BOUNCE_MIN)
    {
        body.velocity = before - body.normal * (into * (1 + def.bounce));
        body.isGrounded = false;
        isBounced = true;
    }
    if (!isRamp && body.velocity.x == 0 && std::abs(before.x) > SHOT_BOUNCE_MIN)
    {
        body.velocity.x = -before.x * def.bounce;
        isBounced = true;
    }
    if (!isRamp && body.velocity.y == 0 && std::abs(before.y) > SHOT_BOUNCE_MIN)
    {
        body.velocity.y = -before.y * def.bounce;
        body.isGrounded = false;
        isBounced = true;
    }
    if (isBounced && attack.bounces > 0)
    {
        ricochet_count(sim, attack);
        attack.lifeStart = attack.time;
    }
    else if (isBounced)
        impact_play(sim, def.kind);
    if (body.isGrounded && body.slope == 0)
        body.velocity.x =
            std::clamp(0.0f, body.velocity.x - def.friction * TICK, body.velocity.x + def.friction * TICK);
    attack.position = {body.box.x + size / 2, body.box.y + size / 2};
    attack.velocity = body.velocity;
    attack.isGrounded = body.isGrounded;
    attack.slope = body.slope;
    attack.angle += body.velocity.x * ROLL_SPIN * TICK / std::max(1.0f, size * PI);
}

// Keeps this tick's pose so drawing can blend from it. New attacks remember their first pose
// so they don't sweep in from where they were spawned.
void Weapons::attack_remember(Attack& attack)
{
    attack.originPrevious = attack.origin;
    attack.positionPrevious = attack.position;
    attack.tipPrevious = attack.tip;
    attack.anglePrevious = attack.angle;
    attack.timePrevious = attack.time;
}

// Moves every attack alpha of the way through the last tick. Only for drawing.
void Weapons::blend(float alpha)
{
    for (Attack& attack : attacks)
    {
        attack.origin = vec2_lerp(attack.originPrevious, attack.origin, alpha);
        attack.position = vec2_lerp(attack.positionPrevious, attack.position, alpha);
        attack.tip = vec2_lerp(attack.tipPrevious, attack.tip, alpha);
        attack.angle = angle_lerp(attack.anglePrevious, attack.angle, alpha);
        attack.time = math_lerp(attack.timePrevious, attack.time, alpha);
    }
}

void Weapons::attack_hit(Sim& sim, Attack& attack, int target, Vec2 point)
{
    const AttackDef& def = *attack.def();
    if (def.kind == ATTACK_ROCKET || def.kind == ATTACK_FIREBALL)
    {
        attack_explode(sim, attack);
        return;
    }
    impact_play(sim, def.kind);

    // Explosions deal full damage at their center, down to a fraction at the edge, by the target's nearest point. A
    // Vacuum's suck bites harder the closer to its muzzle.
    float taper = is_cone(def) ? cone_strength_get(attack, point) : 1;
    taper *= def.kind == ATTACK_GRENADE ? GRENADE_CONTACT_SHARE : 1;
    // The double donk: a marking attack (a grenade's clonk) marks whoever it hits, and a blast from the same owner's
    // same weapon landing on them soon after hits three times as hard, with a sound of its own.
    bool isFighter = target < MAX_FIGHTERS;
    float& donkWindow =
        isFighter ? sim.fighters[target].donkWindow : sim.world.dummies[target - MAX_FIGHTERS].donkWindow;
    int& donkOwner = isFighter ? sim.fighters[target].donkOwner : sim.world.dummies[target - MAX_FIGHTERS].donkOwner;
    int& donkWeapon = isFighter ? sim.fighters[target].donkWeapon : sim.world.dummies[target - MAX_FIGHTERS].donkWeapon;
    bool isMarked = donkWindow > 0 && donkOwner == attack.owner && donkWeapon == attack.weapon;
    if (def.kind == ATTACK_EXPLOSION && isMarked)
    {
        taper *= DONK_DAMAGE;
        donkWindow = 0;
        attack.isDonked = true;
        attack.duration = std::max(attack.duration, DONK_FLASH);
        sim.cues->sound_play(SOUND_DONK);
    }
    if (def.isMarking)
    {
        donkWindow = DONK_WINDOW;
        donkOwner = attack.owner;
        donkWeapon = attack.weapon;
    }
    if (def.kind == ATTACK_EXPLOSION)
    {
        Rect box = target_box(sim, target);
        Vec2 nearest = {std::clamp(attack.position.x, box.x, box.x + box.w),
                        std::clamp(attack.position.y, box.y, box.y + box.h)};
        float edge = std::min(1.0f, vec2_length(nearest - attack.position) / attack.stats.range);
        taper *= 1 - edge * (1 - SPLASH_EDGE);
    }
    int damage = std::max(1.0f, std::round(attack.stats.damage * multiplier_get(attack, point) * taper));
    SoundId sound = hit_sound_get(attack.weapon >= 0 ? WEAPON_DEFS[attack.weapon].hit : HIT_BLUNT, damage);

    attack.hitsLeft--;
    attack.hitCooldown = HIT_INTERVAL;
    // A grenade clonks everyone it passes once, one right after another.
    if (def.kind == ATTACK_GRENADE)
    {
        attack.struck |= target < STRUCK_MAX ? 1u << target : 0;
        attack.hitCooldown = 0;
    }
    attack.isDead |= def.isShot && attack.hitsLeft <= 0;
    if (def.wall == WALL_LATCH)
        hook_attach(sim, attack);
    // Uppercuts knock the way they rise.
    Rect box = target_box(sim, target);
    Vec2 source = def.kind == ATTACK_EXPLOSION ? attack.position : sim.fighters[attack.owner].center_get();
    if (def.kind == ATTACK_UPPERCUT)
        source = Vec2{box.x + box.w / 2, box.y + box.h / 2} - vec2_polar(attack.angle, 1);
    damage_deal(sim,
                {
                    .point = point,
                    .source = source,
                    .hitstop = damage >= HITSTOP_MIN_DAMAGE ? std::min(HITSTOP_MAX, damage * HITSTOP_PER_DAMAGE) : 0,
                    .knock = attack.isGentle ? 0 : def.knock,
                    .amount = damage,
                    .owner = attack.owner,
                    .target = target,
                    .sound = sound,
                });
}

// Tips a dummy the way a sudden push goes (a block, which never leans, ignores it), by its sideways part: a dummy
// stands on its stand, so only its lean feels the push.
static void dummy_push(Dummy& dummy, Vec2 push)
{
    if (dummy.tile < 0)
        dummy.wobbleSpeed += push.x * WOBBLE_PER_SPEED;
}

// Hurts a target with all the feedback: sparks, a number, shake that grows with the damage and a sound. The attacker
// freezes in hitstop, its Boxing Glove adds to the knock, and its Embiggener to the damage.
// Dummies flash and wobble, blocks crack and break, and fighters take the damage themselves. In a race, fighters only
// get knocked about, so there's no number.
void Weapons::damage_deal(Sim& sim, Damage damage)
{
    Fighter& attacker = sim.fighters[damage.owner];
    Rect box = target_box(sim, damage.target);
    damage.amount = std::max(1, (int)std::round(damage.amount * attacker.stat_get(STAT_DAMAGE)));
    float side = box.x + box.w / 2 > attacker.center_get().x ? 1 : -1;
    attacker.hitstop_add(damage.hitstop);
    damage.knock *= attacker.stat_get(STAT_KNOCKBACK);
    bool isCounted = damage.target != damage.owner && !(damage.target < MAX_FIGHTERS && sim.match.is_racing());
    attacker.damageDealt += isCounted ? damage.amount : 0;
    if (damage.target < MAX_FIGHTERS)
        sim.fighters[damage.target].damage_take(sim, damage);
    else
    {
        Dummy& dummy = sim.world.dummies[damage.target - MAX_FIGHTERS];
        dummy.flash = 1;
        dummy_push(dummy, knock_get(damage, {box.x + box.w / 2, box.y + box.h / 2}));
        dummy.health -= damage.amount;
        if (dummy.tile >= 0 && dummy.health <= 0)
            sim.world.block_break(sim, dummy, damage.owner);
    }

    Burst burst = HIT_BURST;
    burst.count += HIT_PARTICLES_PER_DAMAGE * damage.amount;
    sim.cues->burst_spawn(burst, damage.point, side > 0 ? 0 : PI, damage.owner);
    sim.cues->shake_add(damage.amount * SHAKE_PER_DAMAGE);
    sim.cues->sound_play(damage.sound);
    if (damage.target < MAX_FIGHTERS && sim.match.is_racing())
        return;
    sim.cues->number_spawn(damage);
}

// Pebble Helmet: touching another fighter or a dummy (not a block) hurts it, by the level's damage times the usual
// bonus for the fighter's speed, at most once every CONTACT_INTERVAL.
void Weapons::contact_update(Sim& sim, Fighter& fighter)
{
    float base = fighter.stat_get(STAT_CONTACT_DAMAGE);
    fighter.contactCooldown -= TICK;
    if (base <= 0 || !fighter.isAlive || fighter.hitstop > 0 || fighter.contactCooldown > 0)
        return;
    Rect box = fighter.body.box;
    int targets = MAX_FIGHTERS + sim.world.dummies.size();
    for (int target = 0; target < targets; target++)
    {
        bool isFighter = target < MAX_FIGHTERS;
        if (isFighter && (target >= sim.fighterCount || target == fighter.index || !sim.fighters[target].isAlive ||
                          !is_hostile(sim, fighter.index, target)))
            continue;
        if (!isFighter && sim.world.dummies[target - MAX_FIGHTERS].tile >= 0)
            continue;
        Rect other = target_box(sim, target);
        if (!is_rect_overlapping(box, other))
            continue;
        float speed = vec2_length(fighter.body.velocity);
        float bonus = 1 + (SPEED_DAMAGE + fighter.stat_get(STAT_SPEED_DAMAGE)) * speed / SPEED_UNIT;
        int damage = std::max(1.0f, std::round(base * bonus));
        Vec2 point = {(std::max(box.x, other.x) + std::min(box.x + box.w, other.x + other.w)) / 2,
                      (std::max(box.y, other.y) + std::min(box.y + box.h, other.y + other.h)) / 2};
        damage_deal(
            sim, {
                     .point = point,
                     .source = fighter.center_get(),
                     .hitstop = damage >= HITSTOP_MIN_DAMAGE ? std::min(HITSTOP_MAX, damage * HITSTOP_PER_DAMAGE) : 0,
                     .knock = CONTACT_KNOCK,
                     .amount = damage,
                     .owner = fighter.index,
                     .target = target,
                     .sound = hit_sound_get(HIT_BLUNT, damage),
                 });
        fighter.contactCooldown = CONTACT_INTERVAL;
        return;
    }
}

// Every fighter's hovering wisps share one orbit around it: the oldest fill the inner ring, as many as fit round it
// WISP_SPACING apart, and the rest the rings beyond, so a crowd of wisps makes concentric rings. Each ring spreads its
// wisps evenly and spins the other way to the one inside it.
void Weapons::orbits_update(Sim& sim)
{
    orbitClock = std::fmod(orbitClock + TICK, 2 * PI / WISP_SPIN);
    std::vector<Attack*> hovering;
    for (int i = 0; i < sim.fighterCount; i++)
    {
        float scale = sim.fighters[i].scale;
        hovering.clear();
        for (Attack& attack : attacks)
            if (attack.owner == i && attack.def()->isOrbiting && !attack.isDead &&
                (attack.isGathering || attack.time < attack.duration))
                hovering.push_back(&attack);
        int placed = 0;
        for (int ring = 0; placed < (int)hovering.size(); ring++)
        {
            float radius = (WISP_RING + ring * WISP_RING_GAP) * scale;
            int count =
                std::min(std::max(1, (int)(2 * PI * radius / (WISP_SPACING * scale))), (int)hovering.size() - placed);
            float spin = (ring % 2 == 0 ? 1 : -1) * WISP_SPIN * orbitClock;
            for (int k = 0; k < count; k++)
            {
                hovering[placed + k]->orbitRadius = radius;
                hovering[placed + k]->orbitAngle = -PI / 2 + spin + 2 * PI * k / count;
            }
            placed += count;
        }
    }
}

// Letting go of attack sends every wisp gathered in the fighter's orbit at the cursor, oldest first, one after
// another, all of them within WISP_RELEASE_SPAN however many there are.
void Weapons::orbits_release(Fighter& fighter)
{
    int count = 0;
    for (Attack& attack : attacks)
        count += attack.owner == fighter.index && attack.isGathering && !attack.isDead;
    float step = std::min(WISP_LAUNCH_STAGGER, WISP_RELEASE_SPAN / std::max(1, count));
    int launched = 0;
    for (Attack& attack : attacks)
    {
        if (attack.owner != fighter.index || !attack.isGathering || attack.isDead)
            continue;
        attack.isGathering = false;
        attack.duration = attack.time + launched++ * step;
    }
}

// Grimoire teleport: sparkles round the fighter while it gathers, then moves them to the spot marked when it was cast
// (backed off again if their box no longer fits), keeping all their momentum, with a blast there that hurts without
// knocking anyone about. Echoes only make the blast.
void Weapons::teleport_move(Sim& sim, Attack& attack)
{
    Fighter& fighter = sim.fighters[attack.owner];
    attack.radius = 0;
    attack.hitsLeft = 0;
    if (attack.time < attack.duration)
    {
        if (!attack.isCopy)
            sim.cues->burst_spawn(WARP_BURST, fighter.center_get(), 0, attack.owner);
        return;
    }

    attack.isDead = true;
    Vec2 spot = attack.position;
    if (!attack.isCopy && attack.hand == 0 && fighter.isAlive)
    {
        sim.cues->burst_spawn(PORTAL_BURST, fighter.center_get(), 0, attack.owner);
        spot = teleport_spot(sim, fighter, attack.position, vec2_length(attack.position - fighter.center_get()));
        fighter.teleport_to(spot);
        sim.cues->shake_add(attack.def()->shake);
    }
    blast_spawn(sim, {
                         .position = spot,
                         .area = attack.stats.area * attack.scale,
                         .damage = attack.stats.damage,
                         .owner = attack.owner,
                         .sound = SOUND_TELEPORT,
                         .weapon = attack.weapon,
                         .isGentle = true,
                         .isSecondary = attack.isSecondary,
                     });
}

// Tesla Coil: a web of lightning between every weapon the fighter has out in the world (anything but explosions).
// Each piece arcs to its nearest few neighbors within reach, so everything nearby is connected without the
// links growing out of hand for rapid-fire weapons. Each coil makes the links thicker.
std::vector<Capsule> Weapons::chain_get(Sim& sim, Fighter& fighter)
{
    std::vector<Capsule> links;
    if (!fighter.is_trinket_equipped(TRINKET_TESLA))
        return links;

    float range = fighter.stat_get(STAT_ARC_RANGE);
    float radius = TESLA_RADIUS * fighter.trinket_count(TRINKET_TESLA);
    std::vector<Vec2> pieces;
    for (Attack& attack : attacks)
        if (attack.owner == fighter.index && !attack.isDead && attack.def()->kind != ATTACK_EXPLOSION &&
            !is_cone(*attack.def()))
            pieces.push_back(attack.position);

    int count = pieces.size();
    std::vector<bool> isLinked(count * count, false);
    std::vector<std::pair<float, int>> near;
    for (int i = 0; i < count; i++)
    {
        near.clear();
        for (int j = 0; j < count; j++)
        {
            float distance = vec2_length(pieces[j] - pieces[i]);
            if (j != i && distance <= range)
                near.push_back({distance, j});
        }
        int reach = std::min((int)near.size(), TESLA_LINKS);
        std::partial_sort(near.begin(), near.begin() + reach, near.end());
        for (int k = 0; k < reach; k++)
        {
            int j = near[k].second;
            if (isLinked[std::min(i, j) * count + std::max(i, j)])
                continue;
            isLinked[std::min(i, j) * count + std::max(i, j)] = true;
            links.push_back({pieces[i], pieces[j], radius});
        }
    }
    return links;
}

// Shocks every target a fighter's links touch, at most once per interval each.
void Weapons::tesla_update(Sim& sim)
{
    for (int i = 0; i < sim.fighterCount; i++)
    {
        Fighter& fighter = sim.fighters[i];
        float damage = fighter.stat_get(STAT_SHOCK_DAMAGE);
        for (Capsule& link : chain_get(sim, fighter))
        {
            for (int target = 0; target < MAX_FIGHTERS + (int)sim.world.dummies.size(); target++)
            {
                Vec2 point;
                if (!is_target(sim, target, i) || !is_capsule_in_rect(link, target_box(sim, target), point))
                    continue;
                float& shock = target < MAX_FIGHTERS ? sim.fighters[target].shockCooldown
                                                     : sim.world.dummies[target - MAX_FIGHTERS].shockCooldown;
                if (shock > 0)
                    continue;
                shock = TESLA_INTERVAL;
                damage_deal(sim, {.point = point,
                                  .source = fighter.center_get(),
                                  .knock = 0,
                                  .amount = (int)damage,
                                  .owner = i,
                                  .target = target,
                                  .sound = hit_sound_get(HIT_ELECTRIC, (int)damage)});
            }
        }
    }
}

// The paths the held weapon's attack would take if fired now (one per Splitter copy), out to the first wall it can't
// ricochet off (Ricochet bounces it off as many as the shot would) or the attack's reach: curving under gravity for
// arrows, straight for other shots, throws, beams, lashes, mines and hooks, and a teleport's line to where it lands.
// Anything that explodes rings the blast it would make where the path ends (its reach counts from the hand). Melee,
// flames and flails have none, as their paths aren't lines.
std::vector<Path> Weapons::paths_get(Sim& sim, Fighter& fighter)
{
    std::vector<Path> paths;
    int key = fighter.weapon_key(fighter.slot);
    if (key < 0 || (is_busy(fighter, key) && !tether_get(fighter, key, 0)))
        return paths;
    const WeaponDef& weapon = WEAPON_DEFS[fighter.weaponLoadout[key]];
    const LevelDef& level = fighter.level_get(key);
    AttackVariant variant = variant_get(fighter.charge);
    const AttackDef& def = variant == VARIANT_CHARGED ? weapon.charged : weapon.normal;
    AttackKind kind = def.kind;
    AttackStats stats = variant == VARIANT_CHARGED ? level.charged : level.normal;
    if (weapon.mode == FIRE_DRAWN)
        stats = stats_blend(level, fighter.charge);
    if (kind == ATTACK_TELEPORT)
    {
        Vec2 spot = teleport_spot(sim, fighter, fighter.controls.cursor, stats.range);
        Vec2 from = fighter.center_get();
        Path path = {.area = stats.area * def.scale * fighter.stat_get(STAT_ATTACK_SIZE)};
        float length = vec2_length(spot - from);
        for (float traveled = 0; traveled < length; traveled += TRAJECTORY_STEP)
            path.steps.push_back(from + (spot - from) * (traveled / length));
        path.steps.push_back(spot);
        paths.push_back(path);
        return paths;
    }
    // A Vacuum's cone (one per Splitter copy, fanned), from the muzzle out to its reach.
    int splits = fighter.stat_get(STAT_COPIES);
    if (is_cone(def))
    {
        Vec2 muzzle = fighter.hand_get() + fighter.aim * MUZZLE_DISTANCE;
        float reach = stats.range * fighter.stat_get(STAT_ATTACK_SIZE) * (splits > 1 ? SPLIT_SCALE : 1);
        for (int split = 0; split < splits; split++)
        {
            float offset = splits > 1 ? split_offset(kind, split, splits, 1 - fighter.stat_get(STAT_SPREAD_CUT)) : 0;
            Vec2 tip = muzzle + vec2_polar(vec2_angle(fighter.aim) + offset, reach);
            paths.push_back({.steps = {muzzle, tip}, .cone = VACUUM_CONE});
        }
        return paths;
    }
    bool isArrow = kind == ATTACK_ARROW;
    bool isStraight = kind == ATTACK_PROJECTILE || kind == ATTACK_BULLET || kind == ATTACK_ROCKET ||
                      kind == ATTACK_FIREBALL || kind == ATTACK_BEAM || kind == ATTACK_WHIP || kind == ATTACK_MINE ||
                      kind == ATTACK_BOOMERANG || (kind == ATTACK_HOOK && variant != VARIANT_CHARGED);
    if (!isArrow && !isStraight)
        return paths;

    // Each Splitter copy gets its own path, fanned like the copies. Straight paths step along the aim one unit at a
    // time. Arrows fly at their real speed so gravity bends them.
    float area = stats.area * def.scale * fighter.stat_get(STAT_ATTACK_SIZE) * (splits > 1 ? SPLIT_SCALE : 1);
    float reach = std::min(stats.range, TRAJECTORY_REACH);
    for (int split = 0; split < splits; split++)
    {
        float offset = splits > 1 ? split_offset(kind, split, splits, 1 - fighter.stat_get(STAT_SPREAD_CUT)) : 0;
        Vec2 aim = vec2_polar(vec2_angle(fighter.aim) + offset, 1);
        float speed = stats.speed * fighter.stat_get(STAT_PROJECTILE_SPEED) + push_get(fighter, aim);
        Vec2 velocity = isArrow ? aim * speed : aim;
        Attack probe = {.origin = fighter.hand_get(),
                        .angle = vec2_angle(aim),
                        .weapon = fighter.weaponLoadout[key],
                        .isLeft = fighter.is_left()};
        Vec2 point = muzzle_get(probe);
        int bounces = def.isBouncy ? (int)fighter.stat_get(STAT_RICOCHETS) : 0;
        Path path;
        bool isEnded = stats.range <= TRAJECTORY_REACH;
        for (float traveled = area > 0 ? MUZZLE_DISTANCE : 0; traveled < reach; traveled += TRAJECTORY_STEP)
        {
            float time = TRAJECTORY_STEP / std::max(1.0f, vec2_length(velocity));
            Vec2 next = point + velocity * time;
            if (sim.world.is_blocking_at(next))
            {
                isEnded |= bounces <= 0;
                if (bounces-- <= 0)
                    break;
                velocity = reflect_get(sim, point, next, velocity);
                continue;
            }
            velocity.y += def.gravity * time;
            path.steps.push_back(point);
            point = next;
        }
        path.steps.push_back(point);
        path.area = isEnded ? area : 0;
        paths.push_back(path);
    }
    return paths;
}

// Latches the hook where it is, holding until let go, and sets the rope to its fighter's current distance. Charged
// hooks start pulling.
void Weapons::hook_attach(Sim& sim, Attack& attack)
{
    Fighter& fighter = sim.fighters[attack.owner];
    attack.isAttached = true;
    attack.lifetime = LIFETIME_INFINITE;
    attack.isPulling = attack.is_charged();
    attack.hitsLeft = 0;
    attack.length = std::min(vec2_length(fighter.center_get() - attack.position), attack.stats.range);
    sim.cues->sound_play(SOUND_LATCH);
    sim.cues->shake_add(attack.def()->shake);
    sim.cues->burst_spawn(IMPACT_BURST, attack.position, 0, attack.owner);
}

// An instant attack reaches its full range at once along its aim, stopping at the first wall (or, for a latching one,
// the first target), where a latching one latches. Each Ricochet bounce marches its full range again as a segment of
// its own, its falloff starting afresh. A bursting one blows up at its tip, without a push.
void Weapons::instant_launch(Sim& sim, Attack& piece)
{
    const AttackDef& def = *piece.def();
    bool isLatching = def.wall == WALL_LATCH;
    auto isBlocked = [&](Vec2 point) {
        for (int target = 0; isLatching && target < MAX_FIGHTERS + (int)sim.world.dummies.size(); target++)
            if (is_target(sim, target, piece.owner) && is_point_in_rect(point, target_box(sim, target)))
                return true;
        return sim.world.is_blocking_at(point);
    };
    Vec2 start = def.kind == ATTACK_WHIP ? piece.origin : piece.position;
    piece.velocity = {};
    piece.tip = ray_march(start, piece.angle, piece.stats.range, isBlocked);
    if (isLatching)
    {
        piece.position = piece.tip;
        if (sim.world.is_blocking_at(piece.position))
            hook_attach(sim, piece);
        return;
    }
    sim.cues->burst_spawn(SPARK_BURST, piece.tip, piece.angle + PI, piece.owner);
    Attack segment = piece;
    for (int i = 0; i < piece.bounces; i++)
    {
        Vec2 before = segment.tip - vec2_polar(segment.angle, RAY_STEP);
        segment.angle = vec2_angle(reflect_get(sim, before, segment.tip, vec2_polar(segment.angle, 1)));
        segment.position = before;
        segment.tip = ray_march(segment.position, segment.angle, piece.stats.range, isBlocked);
        segment.ricochets++;
        attacks.push_back(segment);
        sim.cues->burst_spawn(SPARK_BURST, segment.tip, segment.angle + PI, piece.owner);
    }
    if (def.isBursting)
        blast_spawn(sim, {
                             .position = piece.tip,
                             .area = piece.stats.area * piece.scale / piece.stats.scale,
                             .damage = piece.stats.damage,
                             .owner = piece.owner,
                             .sound = SOUND_NONE, // the attack's own sound already carries it
                             .weapon = piece.weapon,
                             .isSecondary = piece.isSecondary,
                         });
}

// Pulls a whip's wielder toward a wall its lash (reaching as far as it reaches when fired) meets short of full length.
void Weapons::whip_pull(Sim& sim, Attack& piece)
{
    Fighter& fighter = sim.fighters[piece.owner];
    float reach = reach_at_get(piece);
    Vec2 end = ray_march(piece.origin, piece.angle, reach, [&](Vec2 point) { return sim.world.is_blocking_at(point); });
    Vec2 lash = end - piece.origin;
    if (!piece.isCopy && vec2_length(lash) < reach - RAY_STEP)
        fighter.impulse_add(vec2_normalize(lash) * WHIP_PULL * fighter.stat_get(STAT_MOVEMENT));
}

// Bursts a rocket, mine or fireball into a pushing explosion, keeping the damage raised by any ricochets and cut by
// how far it flew. The
// blast grows with trinkets but not with the attack's own size, so a big fireball keeps its listed area.
void Weapons::attack_explode(Sim& sim, Attack& attack)
{
    attack.isDead = true;
    attack.hitsLeft = 0;
    blast_spawn(sim, {
                         .position = attack.position,
                         .area = blast_area_get(attack),
                         .bonus = strength_get(attack, attack.position),
                         .damage = attack.stats.damage * multiplier_get(attack, attack.position),
                         .owner = attack.owner,
                         .sound = SOUND_EXPLOSION,
                         .weapon = attack.weapon,
                         .isPushing = true,
                         .isSecondary = attack.isSecondary,
                     });
}

// Queues an explosion that hits everything inside it next tick, weaker toward its edge. Pushing blasts fling every
// fighter away from the center, harder the closer they are.
void Weapons::blast_spawn(Sim& sim, Blast blast)
{
    float reach = blast.area * KNOCKBACK_REACH;
    float boxing = blast.owner >= 0 ? sim.fighters[blast.owner].stat_get(STAT_KNOCKBACK) : 1;
    for (int i = 0; i < sim.fighterCount; i++)
    {
        Fighter& fighter = sim.fighters[i];
        Vec2 away = fighter.center_get() - blast.position;
        float distance = vec2_length(away);
        // Shock Absorber softens its wearer's own blasts as weapon movement, and anyone else's as knockback (which the
        // blast's owner's Boxing Glove adds to).
        float absorb =
            i == blast.owner ? fighter.stat_get(STAT_MOVEMENT) : fighter.stat_get(STAT_KNOCKBACK_TAKEN) * boxing;
        if (!blast.isPushing || !fighter.isAlive || distance >= reach)
            continue;
        Vec2 push =
            vec2_normalize(distance > 0 ? away : Vec2{0, -1}) * KNOCKBACK_SPEED * (1 - distance / reach) * absorb;
        fighter.impulse_add(push);
    }
    for (Dummy& dummy : sim.world.dummies)
    {
        Vec2 away = Vec2{dummy.box.x + dummy.box.w / 2, dummy.box.y + dummy.box.h / 2} - blast.position;
        float distance = vec2_length(away);
        if (blast.isPushing && distance < reach)
            dummy_push(dummy, vec2_normalize(away) * KNOCKBACK_SPEED * (1 - distance / reach) * boxing);
    }

    Attack attack = {
        .stats = {.damage = blast.damage, .range = blast.area},
        .origin = blast.position,
        .position = blast.position,
        .tip = blast.position,
        .bonus = blast.bonus,
        .duration = EXPLOSION_DEF.duration,
        .hitsLeft = 1,
        .owner = blast.owner,
        .weapon = blast.weapon,
        .isExplosion = true,
        .isGentle = blast.isGentle,
        .isSecondary = blast.isSecondary,
    };
    attack_remember(attack);
    pending.push_back(attack);
    sim.cues->sound_play(blast.sound);
    sim.cues->shake_add(EXPLOSION_DEF.shake);
    sim.cues->burst_spawn(BLAST_BURST, blast.position, 0, blast.owner);
}

// The whip lashing or hook flying out from this hand, which leaves only the weapon's base in it.
Attack* Weapons::tether_get(Fighter& fighter, int key, int hand)
{
    for (Attack& attack : attacks)
    {
        AttackKind kind = attack.def()->kind;
        if ((kind == ATTACK_WHIP || kind == ATTACK_HOOK) && attack.owner == fighter.index && attack.key == key &&
            attack.hand == hand && !attack.isCopy && !attack.isDead)
            return &attack;
    }
    return nullptr;
}

// Adds the fighter's own attacks it can stand on to the world for its next move: charged boomerangs in flight as
// obstacles it bumps into, and stuck arrows (until they start fading) as ledges it can only land on from above (and
// drop through).
void Weapons::solids_add(Fighter& fighter, World& world)
{
    for (Attack& attack : attacks)
    {
        if (attack.owner != fighter.index || attack.isDead)
            continue;
        AttackKind kind = attack.def()->kind;
        if (kind == ATTACK_BOOMERANG && attack.is_charged())
        {
            float size = attack.radius;
            world.obstacles.push_back({attack.position.x - size, attack.position.y - size, size * 2, size * 2});
        }
        // A stuck arrow's ledge is the box around its hit shape.
        if (kind == ATTACK_ARROW && attack.isAttached && attack.life_get() < attack.lifetime - ARROW_FADE)
        {
            Vec2 low = {std::min(attack.position.x, attack.tip.x), std::min(attack.position.y, attack.tip.y)};
            Vec2 high = {std::max(attack.position.x, attack.tip.x), std::max(attack.position.y, attack.tip.y)};
            float radius = attack.radius;
            world.ledges.push_back(
                {low.x - radius, low.y - radius, high.x - low.x + radius * 2, high.y - low.y + radius * 2});
        }
    }
}

// Whether the fighter has a flail spinning around it.
bool Weapons::is_spinning(Fighter& fighter)
{
    for (Attack& attack : attacks)
        if (attack.owner == fighter.index && attack.def()->kind == ATTACK_SPIN && !attack.isDead)
            return true;
    return false;
}

// The latched grapple hook the fighter is hanging from, if any.
// The attack a continuous weapon (see FireMode) in a weapon slot keeps going from a hand, or none.
Attack* Weapons::continuous_get(Fighter& fighter, int key, int hand)
{
    for (Attack& attack : attacks)
        if (attack.owner == fighter.index && attack.key == key && attack.hand == hand && !attack.isCopy &&
            !attack.isDead && attack.def()->kind == ATTACK_VACUUM)
            return &attack;
    return nullptr;
}

Attack* Weapons::hook_get(Fighter& fighter)
{
    for (Attack& attack : attacks)
        if (attack.owner == fighter.index && attack.def()->kind == ATTACK_HOOK && attack.isAttached && !attack.isDead)
            return &attack;
    return nullptr;
}

// Removes every attack of one kind the fighter owns at once, like all grapple hooks so Splitter copies drop together.
void Weapons::attacks_release(Fighter& fighter, AttackKind kind)
{
    for (Attack& attack : attacks)
        attack.isDead |= attack.owner == fighter.index && attack.def()->kind == kind;
}

// A fresh press calls thrown weapons back: Charge recalls boomerangs once all are out, Attack or Charge
// reels in a flail ball. Reports whether it did.
bool Weapons::is_recalled(Sim& sim, Fighter& fighter)
{
    int key = fighter.weapon_key(fighter.slot);
    if (key < 0)
        return false;
    bool isLeft = fighter.is_pressed(CONTROL_ATTACK);
    bool isRight = fighter.is_pressed(CONTROL_CHARGE);
    bool isBoomerang =
        WEAPON_DEFS[fighter.weaponLoadout[key]].normal.kind == ATTACK_BOOMERANG && isRight && is_busy(fighter, key);
    bool isFlail = false;
    for (Attack& attack : attacks)
        isFlail |= attack.def()->kind == ATTACK_FLAIL && attack.owner == fighter.index && attack.key == key &&
                   !attack.isReturning;
    isFlail &= isLeft || isRight;
    if (!isBoomerang && !isFlail)
        return false;

    for (Attack& attack : attacks)
        attack.isReturning |= attack.owner == fighter.index && attack.key == key;
    return true;
}

float mine_blink_get(Attack& attack)
{
    float left = std::clamp((attack.lifetime - attack.life_get()) / MINE_HURRY, 0.0f, 1.0f);
    return MINE_BLINK_MIN + (MINE_BLINK - MINE_BLINK_MIN) * left;
}

// Whether a Vacuum moves a shot right now: one whose attack drifts, as long as it's loose going its own way (a wisp
// once sent, a flail ball not being reeled in, a grapple out) or stuck to a surface (which it comes loose from).
static bool is_drifting(Attack& shot)
{
    const AttackDef& def = *shot.def();
    bool isOrbiting = def.isOrbiting && shot.velocity.x == 0 && shot.velocity.y == 0;
    bool isWhiffing = def.isInstant && !shot.isAttached;
    return def.isDrifting && !shot.isReturning && !isOrbiting && !isWhiffing;
}

// Gives a shot back a share of the flight it set off with, never more than it's used, which winds back its damage
// falloff with it (a fuse too). One that flies on forever gets back a share of its fade. A hook, whose falloff goes by
// distance, gets back a share of its range.
static void shot_restore(Attack& shot, float share)
{
    AttackKind kind = shot.def()->kind;
    float lifetime = std::isinf(shot.lifetime) ? shot.fade : shot.lifetime;
    shot.lifeStart = std::max(shot.lifeStart, std::min(shot.time, shot.lifeStart + lifetime * share));
    if (kind != ATTACK_HOOK)
        return;

    Vec2 back = shot.position - shot.origin;
    shot.origin = shot.origin + vec2_normalize(back) * std::min(shot.stats.range * share, vec2_length(back));
}

// Moves every shot in an attack's cone (from its position along its aim, out to its range), anyone's: a blow turns each
// to fly straight out of the cone from its point (along the aim, give or take where in the cone it is), at its own
// speed plus the blow's, and pull speeds each toward the point. A shot stuck to a surface comes loose first (a
// grapple's hook too), popping out toward the point at the cone's own speed when pulled, and glancing off the surface
// if it would head straight back in. A claiming attack makes other fighters' shots its owner's, burst into its color
// (all but those tied to their fighter's weapon: on a rope or chain, waiting to be set off, or the weapon itself). The
// owner's own shots then get back restore's share of what they set off with (see shot_restore).
void Weapons::shots_drift(Sim& sim, Attack& source, float blow, float pull, float restore)
{
    for (Attack& shot : attacks)
    {
        AttackKind kind = shot.def()->kind;
        if (&shot == &source || shot.isExplosion || !is_drifting(shot) || !is_in_cone(source, shot.position))
            continue;
        const AttackDef& def = *shot.def();
        bool isTied = def.isTethered || def.isArming || def.isWielded;
        if (source.def()->isClaiming && shot.owner != source.owner && !isTied)
        {
            shot.ownerPrevious = shot.owner;
            shot.owner = source.owner;
            shot.claimTime = shot.time;
            shot.key = -1;
            shot.isSecondary = false;
            shot.struck = 0;
            shot.hitCooldown = 0;
            sim.cues->burst_spawn(SPARK_BURST, shot.position, source.aimAngle, source.owner);
        }
        Vec2 toward = vec2_normalize(source.position - shot.position);
        bool isLoosened = shot.isAttached;
        // Boxing Glove moves shots harder, as it knocks fighters harder.
        float boxing = sim.fighters[source.owner].stat_get(STAT_KNOCKBACK);
        if (isLoosened)
        {
            shot.isAttached = false;
            shot.hitsLeft = kind == ATTACK_ARROW ? shot.def()->hits : shot.hitsLeft;
            shot.velocity = pull > 0 ? toward * source.stats.speed * boxing : Vec2{};
        }
        shot.isHeld |= pull > 0;
        shot.velocity = shot.velocity + toward * pull * boxing;
        if (blow > 0)
            shot.velocity = toward * -(vec2_length(shot.velocity) + blow * boxing);
        Vec2 next = shot.position + shot.velocity * TICK;
        if (isLoosened && sim.world.is_blocking_at(next))
            shot.velocity = reflect_get(sim, shot.position, next, shot.velocity);
        if (shot.def()->isAligned)
            shot.angle = vec2_angle(shot.velocity);
        if (restore > 0 && shot.owner == source.owner)
            shot_restore(shot, restore);
    }
}

// The Vacuum's suck: a long, narrow cone from the muzzle along the aim, following the hand, kept going for as long as
// it's held (the attack control down with it still in that hand). It spins up to its full reach, and let go, it winds
// back down and goes (taken up again on the way down, it spins back up). Fighters in it (and anyone's shots) are
// pulled toward the muzzle, topped up to its pull speed rather than stacking. Once every interval (its cooldown)
// it nibbles at every target whose middle is in the cone. (The air streaming in along it is drawn from the cone, see
// Scene::suck_draw.)
void Weapons::vacuum_move(Sim& sim, Attack& attack)
{
    Fighter& fighter = sim.fighters[attack.owner];
    int hand = fighter.hand_slot_get(attack.hand);
    bool isHeld =
        fighter.isAlive && fighter.is_down(CONTROL_ATTACK) && hand >= 0 && fighter.weapon_key(hand) == attack.key;
    attack.isReturning = !isHeld;
    attack.length = std::clamp(attack.length + (isHeld ? TICK / VACUUM_SPIN_UP : -TICK / VACUUM_SPIN_DOWN), 0.0f, 1.0f);
    attack.isDead = !isHeld && attack.length <= 0;
    for (int i = 0; i < sim.fighterCount; i++)
    {
        Fighter& target = sim.fighters[i];
        Vec2 center = target.center_get();
        if (!is_target(sim, i, attack.owner) || !is_in_cone(attack, center))
            continue;
        // Boxing Glove pulls harder, as it knocks harder.
        float boxing = fighter.stat_get(STAT_KNOCKBACK);
        Vec2 toward = vec2_normalize(attack.position - center);
        float room = std::max(0.0f, attack.stats.speed * boxing - vec2_dot(target.body.velocity, toward));
        float pull = std::min(room, VACUUM_PULL_RATE * boxing * TICK) * target.stat_get(STAT_KNOCKBACK_TAKEN);
        target.body.velocity = target.body.velocity + toward * pull;
    }
    for (int i = 0; i < (int)sim.world.dummies.size(); i++)
    {
        Dummy& dummy = sim.world.dummies[i];
        Vec2 center = {dummy.box.x + dummy.box.w / 2, dummy.box.y + dummy.box.h / 2};
        if (dummy.tile >= 0 || !is_target(sim, MAX_FIGHTERS + i, attack.owner) || !is_in_cone(attack, center))
            continue;
        Vec2 toward = vec2_normalize(attack.position - center);
        dummy.wobbleSpeed += toward.x * VACUUM_PULL_RATE * fighter.stat_get(STAT_KNOCKBACK) * WOBBLE_PER_PULL * TICK;
    }
    // Each interval (the hit cooldown counting it down), everyone in the cone can be nibbled again.
    float interval = fighter.level_get(attack.key).cooldown / fighter.stat_get(STAT_ATTACK_RATE);
    bool isPulse = attack.hitCooldown <= 0;
    if (isPulse)
    {
        attack.struck = 0;
        attack.hitCooldown = interval;
    }
    int targets = std::min(MAX_FIGHTERS + (int)sim.world.dummies.size(), STRUCK_MAX);
    for (int target = 0; target < targets; target++)
    {
        Rect box = target_box(sim, target);
        Vec2 center = {box.x + box.w / 2, box.y + box.h / 2};
        if ((attack.struck >> target & 1) || !is_target(sim, target, attack.owner) || !is_in_cone(attack, center))
            continue;
        attack.struck |= 1u << target;
        attack_hit(sim, attack, target, center);
    }
    // Only the first of a fan of copies (or repeats) lengthens lives, so they don't add up.
    bool isLengthening = isPulse && !attack.isCopy;
    shots_drift(sim, attack, 0, VACUUM_PULL_RATE * TICK, isLengthening ? VACUUM_RESTORE : 0);
}

// The Vacuum's airblast: once, as it goes off, its cone hits everyone in it for a little damage and knocks every
// fighter in it away (launching them), both harder the closer they are, and turns every shot in it to fly out along
// the aim, claiming other fighters' (all as good as fresh, see shots_drift). (The air it blows out is drawn from the
// cone, see Scene::gust_draw.)
void Weapons::gust_move(Sim& sim, Attack& attack)
{
    attack.isDead = attack.life_get() >= attack.lifetime;
    if (attack.time > 0)
        return;
    int targets = std::min(MAX_FIGHTERS + (int)sim.world.dummies.size(), STRUCK_MAX);
    for (int target = 0; target < targets; target++)
    {
        Rect box = target_box(sim, target);
        Vec2 center = {box.x + box.w / 2, box.y + box.h / 2};
        if (!is_target(sim, target, attack.owner) || !is_in_cone(attack, center))
            continue;
        attack_hit(sim, attack, target, center);
        // Boxing Glove adds to it as to any knock.
        Vec2 push = vec2_normalize(center - attack.position) * attack.stats.speed * cone_strength_get(attack, center) *
                    sim.fighters[attack.owner].stat_get(STAT_KNOCKBACK);
        if (target >= MAX_FIGHTERS)
        {
            dummy_push(sim.world.dummies[target - MAX_FIGHTERS], push);
            continue;
        }
        Fighter& fighter = sim.fighters[target];
        fighter.knock_take(push * fighter.stat_get(STAT_KNOCKBACK_TAKEN), attack.owner);
    }
    shots_drift(sim, attack, attack.stats.speed * GUST_SHOT_SHARE, 0, attack.isCopy ? 0 : GUST_RESTORE);
}

// A weapon (by its key, see Fighter::weapon_key) is busy once as many of it are out of the hand (wielded attacks) as
// its level allows. Splitter and Doubler copies don't count.
bool Weapons::is_busy(Fighter& fighter, int key)
{
    int out = 0;
    for (Attack& attack : attacks)
    {
        out += attack.owner == fighter.index && attack.key == key && !attack.isDead && !attack.isCopy &&
               attack.def()->isWielded;
    }
    return out >= fighter.level_get(key).count;
}